docs(issue-42): stages 1-2 - SKILL.md code-block inventory as test data; remove blocks the scripts already do

Stage 1: tests/data/skill_code_blocks.json lists all 37 fenced blocks of the
eight SKILL.md files at base 45d1621 (indented fences count), classed (a)
duplicate of a script, (b) procedure no script offers, (c) example/call/
diagram, with script file:line evidence and recorded mismatches.
tests/test_issue42_skill_blocks.py fails when a block changes without the
inventory, an (a) block comes back, a removed block's entry call is missing,
an exit-code table drifts from the script, or evidence points nowhere.

Stage 2: the five (a) blocks are gone - resume Workflow, stop pre-flight,
create pre-flight / Workflow / manual YAML append - replaced by the
entry-point call with option and exit-code tables. Each exit table has a
catch-all row: under set -e a failing sub-step's code passes through.
create's exit 4 is real (the YAML write raises SystemExit(4) for a duplicate
running row) and is listed as such. Doc-to-script mismatches are fixed in the
doc (resume Case 3 / no attach, stop --purge-conversation --yes, status
--json keys, create cmd_full and the nonexistent yaml-edit script). No
behaviour change, no version bump.

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

.agents/skills/multi-agent-mux-status/SKILL.md

@@ -73,31 +73,40 @@ lab-paper-pdf2md-creator-claude              default      running    alive  clau
 
 ```json
 {
-  "yaml_path": "...",
-  "herdr_sessions_alive": ["..."],
-  "yaml_entries": [...],
-  "rows": [
+  "timestamp": "2026-06-19T14:20:00Z",
+  "yaml_path": ".../.mam/agent-sessions.yaml",
+  "herdr_sessions_alive": ["lab-landing-page-creator-claude|default"],
+  "herdr_confirmed": true,
+  "drifts": [
+    {"class": "A", "name": "lab-landing-page-creator-agy", "msg": "..."}
+  ],
+  "actions": [],
+  "sessions_detail": [
     {
       "name": "lab-landing-page-creator-claude",
-      "yaml_status": "running",
+      "server": "default",
+      "herdr_workspace": "landing-page",
+      "status": "running",
       "herdr_alive": true,
-      "pane_cmd": "claude",
+      "cmd": "claude",
+      "role": "creator",
+      "resume_state": "yes",
+      "job_id": null,
+      "job_status": null,
       "pane_cwd": "/home/.../refer_landing_page",
-      "resume_uuid_on_disk": true,
-      "drift": null
-    },
-    {
-      "name": "lab-landing-page-creator-agy",
-      "yaml_status": "terminated",
-      "herdr_alive": false,
-      "drift": "yaml-says-terminated-but-disk-uuid-still-present"
+      "attach_command": "HERDR_SESSION_NAME=default herdr agent attach lab-landing-page-creator-claude",
+      "drift_classes": [],
+      "pane_pid": 12345,
+      "cmd_full": "claude --dangerously-skip-permissions --session-id <uuid>",
+      "start_command": "...",
+      "last_visible_status": "pinned"
     }
-  ],
-  "unregistered": [],
-  "drifts": []
+  ]
 }
 ```
 
+The top-level keys other than `sessions_detail` are `reconcile.sh --once --emit-diff --dry-run`'s output, passed through unchanged. `resume_state` is `yes`, `MISSING`, `scan` or `no`.
+
 ## Drift classes (read-only — never mutates)
 
 | Class | Detection | Meaning |