feat: multi-agent-mux-update skill and in-place install (Issue #72)

The update is a skill (decision 4); deploy/update.sh and the installed
.mam_deploy/update.sh are gone.

- Phase 1 (installed code, update.sh): publish the update marker under the
  exclusive admission lock; refuse before any change while a running row, a
  live herdr agent in the workspace on any running server, an open job
  (unreadable JSON included, dry_run not), a live loop marker or a
  monitor.lock held by a monitor the skills did not start (U3) is there - the
  calling agent (server + pane, its row and one running job) excepted
  (lib_py/update.py precheck, decisions 1 and 7). Stop the monitor (TERM, then
  KILL and restart it if it does not end; decision 2), handle a leftover
  backup by its state (U4), back up .agents, .mam_deploy, root files, .venv,
  the installer's .mam files and the registry (SQLite backup API under the
  registry lock) into .mam/update-backup/, then exec a copy of
  install_phase.sh outside the tree (decision 5).
- The copy (no lib.sh/lib_py, bash 3.2) runs the installer in place; on
  failure it restores the backup and restarts the monitor from the restored
  tree; on success it runs phase 2, post_update.sh of the new tree, which
  converts the registry with lib_py.registry_format and restarts the monitor
  if it ran. The backup and the marker are removed at the end.
- install.sh updates in place (decisions 3, 4, 9): install_state keys are set,
  one line each; no updater is installed and an old one (.mam_deploy/update.sh,
  or a root update.sh the manifest lists) is removed; framework files the new
  version no longer ships are deleted when unmodified, kept and listed when
  modified, and dropped from base/, the manifest and asset_hashes.txt; a local
  source's .mam is not staged. remove.sh knows the new skill; CI shellchecks
  its scripts; docs point at the skill.
- test_issue8_update_state and test_deploy_layout td6/td27 run the skill.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/README.md

@@ -9,7 +9,7 @@ This directory contains packaging templates and installation scripts to deploy t
 *   **`install.sh`**: A self-contained, idempotent remote shell installer (via curl) that checks system requirements (`herdr`, `python3`), sets up a local python virtual environment (`.venv`), and performs 3-way refresh with key-level registry merge (Rev.2).
 *   **`install_mam.sh`**: A local-clone installer that copies rules/skills (`.agents/`), `AGENTS.md`, manifests, and asset hashes into target projects.
 *   **`lib_ownership.sh`**: Single source of truth for framework-owned files and key-level registry files.
-*   **`update.sh`**: In-place updater script installed into target `.mam_deploy/update.sh`.
+*   **Updates**: installed workspaces update with the `multi-agent-mux-update` skill (`bash .agents/skills/multi-agent-mux-update/scripts/update.sh`).
 *   **`remove.sh`**: Clean uninstaller script installed into target `.mam_deploy/remove.sh`.
 *   **`generate-env.sh`**: Environment configuration bootstrap helper.
 *   **`INSTALL.md`**: Detailed installation and quick-start user manual.
@@ -40,7 +40,7 @@ bash deploy/install_mam.sh --target /path/to/your/project
 Refer to **`INSTALL.md`** inside this directory for the full instructions and workflows.
 
 > [!NOTE]
-> `install_mam.sh` automatically deploys `.mam_deploy/update.sh` and `.mam_deploy/remove.sh` into target workspaces, recording install manifests and asset hashes to enable clean updates and uninstalls.
+> `install_mam.sh` automatically deploys `.mam_deploy/remove.sh` into target workspaces, recording install manifests and asset hashes to enable clean updates and uninstalls.
 
 ### 3. Custom Fork / Private Mirror Installations
 If you run a private mirror or fork, you can override the source URLs during installation using environment variables:
@@ -53,7 +53,7 @@ curl -fsSL https://my-mirror.example.com/.../install.sh \
     bash
 
 # Updating an existing workspace against a mirror
-MAM_INSTALLER_URL=https://my-mirror.example.com/.../install.sh bash deploy/update.sh
+MAM_INSTALLER_URL=https://my-mirror.example.com/.../install.sh bash .agents/skills/multi-agent-mux-update/scripts/update.sh
 ```
 
 ### 4. Registering as a Workspace Plugin

deploy/gitea-ci.yml

@@ -41,7 +41,7 @@ jobs:
           shellcheck deploy/install.sh
           shellcheck deploy/install_mam.sh
           shellcheck deploy/generate-env.sh
-          shellcheck deploy/update.sh
+          shellcheck .agents/skills/multi-agent-mux-update/scripts/*.sh
           shellcheck deploy/remove.sh
           echo "✅ ShellCheck completed successfully."
 

deploy/install.sh

@@ -125,7 +125,9 @@ if [ "$REFRESH" -eq 1 ] || [ "${MAM_SKIP_VENV:-0}" -eq 1 ] || ! check_assets_pre
   FETCH_METHOD="archive"
   if [ -d "$REPO_URL" ]; then
     echo "🌐 Copying local working tree into a staging area..."
-    cp -R "$REPO_URL/." "$STAGE_DIR/"
+    # Everything but .mam/: runtime state is never staged, and it may hold the
+    # update skill's rollback copy (.mam/update-backup/, Issue #72).
+    find "$REPO_URL/." -mindepth 1 -maxdepth 1 ! -name .mam -exec cp -R {} "$STAGE_DIR/" \;
     FETCH_METHOD="local"
   elif command -v git &>/dev/null; then
     echo "🌐 Cloning repository (shallow) into a staging area..."
@@ -157,9 +159,15 @@ if [ "$REFRESH" -eq 1 ] || [ "${MAM_SKIP_VENV:-0}" -eq 1 ] || ! check_assets_pre
   MANIFEST_FILE=".mam/install_manifest.txt"
   touch "$MANIFEST_FILE"
 
-  # Migrate legacy root layout for remove.sh and update.sh into .mam_deploy/ if owned
+  # Drop every line naming this path from the manifest
+  manifest_drop() {
+    grep -Fvx -- "$1" "$MANIFEST_FILE" > "$MANIFEST_FILE.tmp" || true
+    mv -f "$MANIFEST_FILE.tmp" "$MANIFEST_FILE"
+  }
+
+  # Migrate legacy root layout for remove.sh into .mam_deploy/ if owned
   mkdir -p .mam_deploy
-  for legacy_script in remove.sh update.sh; do
+  for legacy_script in remove.sh; do
     if [ -f "$legacy_script" ] && grep -Fqx "$legacy_script" "$MANIFEST_FILE" 2>/dev/null; then
       mv -f "$legacy_script" ".mam_deploy/$legacy_script"
       python3 -c '
@@ -179,6 +187,13 @@ with open(path, "w") as f:
     fi
   done
 
+  # update.sh is no longer shipped (Issue #72; the multi-agent-mux-update skill
+  # updates). A legacy root update.sh goes only if the manifest says we put it there.
+  if [ -f update.sh ] && grep -Fqx update.sh "$MANIFEST_FILE" 2>/dev/null; then
+    rm -f update.sh
+    manifest_drop update.sh
+  fi
+
   # Safe refresh & fingerprint checking logic
   TS=$(date -u +%Y%m%dT%H%M%SZ)
   FRAMEWORK_LEDGER=".mam/.framework_ledger.tmp"
@@ -374,7 +389,7 @@ MERGEREG
     fi
   done
 
-  # Install remove.sh and update.sh into .mam_deploy/
+  # Install remove.sh into .mam_deploy/
   mkdir -p .mam_deploy
   if [ -f "$STAGE_DIR/deploy/remove.sh" ]; then
     cp "$STAGE_DIR/deploy/remove.sh" .mam_deploy/remove.sh
@@ -384,13 +399,9 @@ MERGEREG
     fi
   fi
 
-  if [ -f "$STAGE_DIR/deploy/update.sh" ]; then
-    cp "$STAGE_DIR/deploy/update.sh" .mam_deploy/update.sh
-    chmod 0755 .mam_deploy/update.sh
-    if ! grep -Fqx ".mam_deploy/update.sh" "$MANIFEST_FILE" 2>/dev/null; then
-      echo ".mam_deploy/update.sh" >> "$MANIFEST_FILE"
-    fi
-  fi
+  # An older install's updater is not shipped any more (Issue #72)
+  rm -f .mam_deploy/update.sh
+  manifest_drop .mam_deploy/update.sh
 
   if [ -f "$STAGE_DIR/.mam.env.example" ] && [ ! -e ".mam.env.example" ]; then
     cp "$STAGE_DIR/.mam.env.example" .
@@ -407,6 +418,34 @@ MERGEREG
     fi
   fi
 
+  # Framework-owned files the previous install recorded (manifest and
+  # asset_hashes.txt) that this version no longer ships (Issue #72). Unmodified
+  # ones are deleted. Modified ones are kept and become the user's file: they
+  # leave the manifest, so remove.sh leaves them alone, and asset_hashes.txt
+  # (rebuilt below from the shipped files only).
+  if [ -f .mam/asset_hashes.txt ]; then
+    SHIPPED_LIST=".mam/.shipped_paths.tmp"
+    cut -f2 "$FRAMEWORK_LEDGER" > "$SHIPPED_LIST"
+    while read -r _old_sha _old_path; do
+      [ -n "${_old_path:-}" ] || continue
+      is_framework_owned "$_old_path" || continue
+      grep -Fqx -- "$_old_path" "$MANIFEST_FILE" || continue
+      if grep -Fqx -- "$_old_path" "$SHIPPED_LIST"; then continue; fi
+      if [ -f "$_old_path" ] && [ "$(python3 -c 'import hashlib, sys; print(hashlib.sha256(open(sys.argv[1], "rb").read()).hexdigest())' "$_old_path")" != "$_old_sha" ]; then
+        echo "ℹ️  Local modification detected (no longer shipped, kept as yours): $_old_path" >&2
+      else
+        rm -f "$_old_path"
+        _old_dir="$(dirname "$_old_path")"
+        while [ "$_old_dir" != ".agents" ] && rmdir "$_old_dir" 2>/dev/null; do
+          _old_dir="$(dirname "$_old_dir")"
+        done
+      fi
+      rm -f ".mam/base/$_old_path"
+      manifest_drop "$_old_path"
+    done < .mam/asset_hashes.txt
+    rm -f "$SHIPPED_LIST"
+  fi
+
   # Re-build asset_hashes.txt from the UPSTREAM copy of every framework-owned file
   python3 - .mam/asset_hashes.txt "$FRAMEWORK_LEDGER" <<'HASHDB'
 import os, hashlib, sys
@@ -590,15 +629,25 @@ with open(gi_path, "w") as f:
 PY
 
 if [ "${MAM_SKIP_GITIGNORE:-0}" -eq 0 ]; then
+  # Set the key: overwrite it in place, one line per key, other keys kept
   python3 -c '
 import os
+os.makedirs(".mam", exist_ok=True)
+lines = []
 if os.path.exists(".mam/install_state"):
-    with open(".mam/install_state", "a") as f:
-        f.write("gitignore_created=1\n")
-else:
-    os.makedirs(".mam", exist_ok=True)
-    with open(".mam/install_state", "w") as f:
-        f.write("gitignore_created=1\n")
+    with open(".mam/install_state") as f:
+        lines = f.read().splitlines()
+out, done = [], False
+for line in lines:
+    if line.startswith("gitignore_created="):
+        if done:
+            continue
+        line, done = "gitignore_created=1", True
+    out.append(line)
+if not done:
+    out.append("gitignore_created=1")
+with open(".mam/install_state", "w") as f:
+    f.write("\n".join(out) + "\n")
 '
 fi
 
@@ -617,6 +666,6 @@ cat <<EOF
      $ bash .agents/skills/multi-agent-mux-status/scripts/status.sh
 
   3. Update installed skills in the future:
-     $ bash .mam_deploy/update.sh
+     $ bash .agents/skills/multi-agent-mux-update/scripts/update.sh
 --------------------------------------------------------------------------------
 EOF

deploy/install_mam.sh

@@ -132,16 +132,12 @@ if [ -f "$SRC_DIR/.mam.env.example" ]; then
   log_ok "Copied .mam.env.example configuration template"
 fi
 
-# Deploy remove.sh and update.sh into .mam_deploy/ (R-3)
+# Deploy remove.sh into .mam_deploy/ (R-3)
 mkdir -p "$TARGET_DIR/.mam_deploy"
 if [ -f "$SRC_DIR/deploy/remove.sh" ]; then
   cp "$SRC_DIR/deploy/remove.sh" "$TARGET_DIR/.mam_deploy/remove.sh"
   chmod 0755 "$TARGET_DIR/.mam_deploy/remove.sh"
 fi
-if [ -f "$SRC_DIR/deploy/update.sh" ]; then
-  cp "$SRC_DIR/deploy/update.sh" "$TARGET_DIR/.mam_deploy/update.sh"
-  chmod 0755 "$TARGET_DIR/.mam_deploy/update.sh"
-fi
 
 if [ -f "$SRC_DIR/deploy/generate-env.sh" ]; then
   mkdir -p "$TARGET_DIR/scripts"
@@ -161,7 +157,7 @@ mkdir -p "$TARGET_DIR/.mam"
 MANIFEST_FILE="$TARGET_DIR/.mam/install_manifest.txt"
 : > "$MANIFEST_FILE"
 ( cd "$TARGET_DIR" && find .agents -type f -print ) >> "$MANIFEST_FILE"
-for extra in ".mam.env.example" ".mam_deploy/remove.sh" ".mam_deploy/update.sh" \
+for extra in ".mam.env.example" ".mam_deploy/remove.sh" \
              "scripts/generate-env.sh"; do
   if [ -e "$TARGET_DIR/$extra" ]; then
     echo "$extra" >> "$MANIFEST_FILE"

deploy/remove.sh

@@ -92,6 +92,7 @@ else
     ".agents/skills/multi-agent-mux-resume"
     ".agents/skills/multi-agent-mux-status"
     ".agents/skills/multi-agent-mux-stop"
+    ".agents/skills/multi-agent-mux-update"
     ".agents/hooks"
     ".agents/hooks.json"
     ".agents/MULTI_AGENT_RULES.md"

deploy/update.sh

@@ -1,269 +0,0 @@
-#!/usr/bin/env bash
-# ==============================================================================
-# update.sh — Multi-Agent Mux (MAM) Orchestration Updater
-# ==============================================================================
-# Safely updates MAM skills, virtual environment, and docs to the latest version.
-# Preserves user configuration (.env) and local metadata/jobs database (.mam).
-# ==============================================================================
-set -euo pipefail
-
-TARGET_DIR=""
-FORCE=0
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-
-# Parse arguments
-while [[ $# -gt 0 ]]; do
-  case "$1" in
-    -y|--yes|--force)
-      FORCE=1
-      shift
-      ;;
-    *)
-      TARGET_DIR="$1"
-      shift
-      ;;
-  esac
-done
-
-if [ -z "$TARGET_DIR" ]; then
-  if [ "$(basename "$SCRIPT_DIR")" = ".mam_deploy" ]; then
-    TARGET_DIR="$(dirname "$SCRIPT_DIR")"
-  else
-    TARGET_DIR="$(pwd)"
-  fi
-else
-  if [ "$(basename "$TARGET_DIR")" = ".mam_deploy" ]; then
-    TARGET_DIR="$(dirname "$TARGET_DIR")"
-  fi
-  if [ ! -d "$TARGET_DIR" ]; then
-    echo "❌ Error: Target directory '$TARGET_DIR' does not exist." >&2
-    exit 1
-  fi
-  TARGET_DIR="$(cd "$TARGET_DIR" && pwd)"
-fi
-
-echo "===================================================================="
-echo "⚡ Starting Multi-Agent Mux (MAM) Update"
-echo "📂 Target Workspace: $TARGET_DIR"
-echo "===================================================================="
-
-cd "$TARGET_DIR"
-
-# 1. Verification of existing install (B-2: dual resolution)
-REMOVER=""
-for cand in ".mam_deploy/remove.sh" "remove.sh"; do
-  if [ -f "$cand" ]; then
-    REMOVER="$cand"
-    break
-  fi
-done
-
-if [ -z "$REMOVER" ]; then
-  echo "❌ Error: No MAM installation (remove.sh) found in '$TARGET_DIR'." >&2
-  echo "   Please run install.sh first to set up the workspace." >&2
-  exit 1
-fi
-
-# Request confirmation if not forced
-if [ $FORCE -eq 0 ]; then
-  echo "⚠️  WARNING: This will update MAM orchestration skills, virtual environment, "
-  echo "   and docs to the latest version."
-  echo "   (Your configuration, job history, and custom skills will be preserved)."
-  if [ ! -t 0 ]; then
-    echo "❌ Error: Non-interactive terminal detected. Please run with -y/--yes/--force." >&2
-    exit 1
-  fi
-  if ! read -p "❓ Proceed with update? [y/N]: " -r response; then
-    response="n"
-  fi
-  if [[ ! "$response" =~ ^[yY](es)?$ ]]; then
-    echo "❌ Update cancelled by user."
-    exit 0
-  fi
-fi
-
-# 1.5 Pre-capture legacy ownership before remove.sh deletes the manifest (M-4)
-MAM_LEGACY_ENV_OWNED=0
-if [ -f ".mam/install_manifest.txt" ] && grep -Fqx ".env" ".mam/install_manifest.txt" 2>/dev/null; then
-  MAM_LEGACY_ENV_OWNED=1
-fi
-export MAM_LEGACY_ENV_OWNED
-
-# 2. Stage backups of user configurations and metadata to prevent deletion
-echo "💾 Backing up configuration and database..."
-HAS_ENV=0
-ENV_BACKUP_SRC=""
-ENV_BACKUP_TMP=""
-
-if [ -f ".mam.env" ]; then
-  HAS_ENV=1
-  ENV_BACKUP_SRC=".mam.env"
-  ENV_BACKUP_TMP=".mam.env.update-tmp"
-  mv ".mam.env" "$ENV_BACKUP_TMP"
-elif [ -f ".env" ]; then
-  HAS_ENV=1
-  ENV_BACKUP_SRC=".env"
-  ENV_BACKUP_TMP=".env.update-tmp"
-  mv ".env" "$ENV_BACKUP_TMP"
-fi
-
-HAS_MAM=0
-if [ -d ".mam" ]; then
-  HAS_MAM=1
-  # Copy database and jobs to temporary backup outside of .mam.
-  # We do NOT move the .mam folder away so that remove.sh can still read .mam/install_manifest.txt!
-  mkdir -p .mam.update-tmp
-  # Copy SQLite databases and session files
-  for db in .mam/agent-sessions.*; do
-    if [ -f "$db" ]; then
-      cp -f "$db" .mam.update-tmp/
-    fi
-  done
-  # Copy jobs history
-  if [ -d ".mam/jobs" ] && [ "$(ls -A .mam/jobs 2>/dev/null)" ]; then
-    mkdir -p .mam.update-tmp/jobs
-    cp -rf .mam/jobs/* .mam.update-tmp/jobs/
-  fi
-  # Copy delegate logs
-  if [ -d ".mam/delegate_job_logs" ] && [ "$(ls -A .mam/delegate_job_logs 2>/dev/null)" ]; then
-    mkdir -p .mam.update-tmp/delegate_job_logs
-    cp -rf .mam/delegate_job_logs/* .mam.update-tmp/delegate_job_logs/
-  fi
-  # Copy manifest so we have a backup
-  if [ -f ".mam/install_manifest.txt" ]; then
-    cp -f .mam/install_manifest.txt .mam.update-tmp/
-  fi
-  # C12: Copy MAM state files across update cycle
-  for st in install_state asset_hashes.txt version.txt; do
-    if [ -f ".mam/$st" ]; then
-      cp -f ".mam/$st" .mam.update-tmp/
-    fi
-  done
-  if [ -d ".mam/skill-backups" ]; then
-    mkdir -p .mam.update-tmp/skill-backups
-    cp -rf .mam/skill-backups/* .mam.update-tmp/skill-backups/ 2>/dev/null || true
-  fi
-fi
-
-# Define trap to restore backup files on failure
-restore_on_failure() {
-  echo "❌ Update failed. Reverting configuration and database to previous state..."
-  if [ $HAS_ENV -eq 1 ] && [ -n "$ENV_BACKUP_TMP" ] && [ -f "$ENV_BACKUP_TMP" ]; then
-    mv -f "$ENV_BACKUP_TMP" "$ENV_BACKUP_SRC" 2>/dev/null || true
-  fi
-  if [ $HAS_MAM -eq 1 ] && [ -d ".mam.update-tmp" ]; then
-    # Revert to old database/jobs backup by restoring .mam directory
-    rm -rf .mam 2>/dev/null || true
-    mkdir -p .mam
-    cp -f .mam.update-tmp/agent-sessions.* .mam/ 2>/dev/null || true
-    if [ -d ".mam.update-tmp/jobs" ]; then
-      cp -rf .mam.update-tmp/jobs .mam/ 2>/dev/null || true
-    fi
-    if [ -d ".mam.update-tmp/delegate_job_logs" ]; then
-      cp -rf .mam.update-tmp/delegate_job_logs .mam/ 2>/dev/null || true
-    fi
-    if [ -f ".mam.update-tmp/install_manifest.txt" ]; then
-      cp -f .mam.update-tmp/install_manifest.txt .mam/ 2>/dev/null || true
-    fi
-    for st in install_state asset_hashes.txt version.txt; do
-      if [ -f ".mam.update-tmp/$st" ]; then
-        cp -f ".mam.update-tmp/$st" .mam/ 2>/dev/null || true
-      fi
-    done
-    if [ -d ".mam.update-tmp/skill-backups" ]; then
-      mkdir -p .mam/skill-backups
-      cp -rf .mam.update-tmp/skill-backups/* .mam/skill-backups/ 2>/dev/null || true
-    fi
-    rm -rf .mam.update-tmp 2>/dev/null || true
-  fi
-}
-trap restore_on_failure EXIT
-
-# 3. Perform uninstallation of existing files
-echo "🗑️  Removing existing installation..."
-# remove.sh will run in manifest mode because .mam/install_manifest.txt is still present.
-# It will delete .agents/, documents, scripts, .venv, and .mam folder.
-bash "$REMOVER" --force "$TARGET_DIR"
-
-# 4. Fetch and run the latest installer from Gitea
-echo "📥 Fetching and running the latest installer..."
-# Note: MAM_*_URL environment variables are automatically inherited by the child installer bash process.
-INSTALLER_URL="${MAM_INSTALLER_URL:-https://git.godopu.com/tmpl/multi-agent-mux/raw/branch/main/deploy/install.sh}"
-if command -v curl &>/dev/null; then
-  curl -fsSL "$INSTALLER_URL" | bash -s -- "$TARGET_DIR"
-elif command -v wget &>/dev/null; then
-  wget -qO- "$INSTALLER_URL" | bash -s -- "$TARGET_DIR"
-else
-  echo "❌ Error: Neither 'curl' nor 'wget' is available to fetch the installer." >&2
-  exit 1
-fi
-
-# Disable failure trap since installation succeeded
-trap - EXIT
-
-# 5. Restore backups of configuration and database
-echo "🔄 Restoring configuration and database..."
-if [ $HAS_ENV -eq 1 ] && [ -n "$ENV_BACKUP_TMP" ] && [ -f "$ENV_BACKUP_TMP" ]; then
-  if [ "$MAM_LEGACY_ENV_OWNED" = "1" ] && [ "$ENV_BACKUP_SRC" = ".env" ] && [ ! -f ".mam.env" ]; then
-    mv -f "$ENV_BACKUP_TMP" ".mam.env"
-    chmod 0600 ".mam.env" 2>/dev/null || true
-  else
-    mv -f "$ENV_BACKUP_TMP" "$ENV_BACKUP_SRC"
-  fi
-fi
-
-if [ $HAS_MAM -eq 1 ]; then
-  if [ -d ".mam.update-tmp" ]; then
-    # The installer created a new .mam directory with a new manifest.
-    # We want to merge the old .mam database/jobs back while keeping the new manifest.
-    for db in .mam.update-tmp/agent-sessions.*; do
-      if [ -f "$db" ]; then
-        cp -f "$db" .mam/
-      fi
-    done
-    if [ -d ".mam.update-tmp/jobs" ] && [ "$(ls -A .mam.update-tmp/jobs 2>/dev/null)" ]; then
-      mkdir -p .mam/jobs
-      cp -rf .mam.update-tmp/jobs/* .mam/jobs/
-    fi
-    if [ -d ".mam.update-tmp/delegate_job_logs" ] && [ "$(ls -A .mam.update-tmp/delegate_job_logs 2>/dev/null)" ]; then
-      mkdir -p .mam/delegate_job_logs
-      cp -rf .mam.update-tmp/delegate_job_logs/* .mam/delegate_job_logs/
-    fi
-    # Issue #8: asset_hashes.txt and version.txt describe the tree the
-    # installer just wrote, so the pre-update copies must NOT come back here -
-    # restoring them made version.txt name the previous commit and remove.sh
-    # treat every updated file as locally modified (spurious backups). Only
-    # install_state carries history worth keeping: merge in any key the fresh
-    # install did not write (e.g. gitignore_created from the original install).
-    # The failure path (restore_on_failure) still puts all three back verbatim.
-    if [ -f ".mam.update-tmp/install_state" ]; then
-      touch .mam/install_state
-      # A fresh install_state without a final newline would glue the first
-      # merged key onto its last line.
-      if [ -s .mam/install_state ] && [ -n "$(tail -c1 .mam/install_state)" ]; then
-        printf '\n' >> .mam/install_state
-      fi
-      while IFS= read -r line || [ -n "$line" ]; do
-        case "$line" in
-          *=*) ;;
-          *) continue ;;   # not a key=value line
-        esac
-        key="${line%%=*}"
-        [ -n "$key" ] || continue
-        # exact key match, no regex interpretation of the key
-        if ! awk -F= -v k="$key" '$1 == k { found = 1 } END { exit !found }' .mam/install_state; then
-          printf '%s\n' "$line" >> .mam/install_state
-        fi
-      done < .mam.update-tmp/install_state
-    fi
-    if [ -d ".mam.update-tmp/skill-backups" ]; then
-      mkdir -p .mam/skill-backups
-      cp -rf .mam.update-tmp/skill-backups/* .mam/skill-backups/ 2>/dev/null || true
-    fi
-    rm -rf ".mam.update-tmp"
-  fi
-fi
-
-echo "===================================================================="
-echo "🎉 Update complete!"
-echo "===================================================================="