feat(header): add smart sticky scroll animation and styling refinements

- Implement RAF-throttled smart sticky scroll interaction on app header
- Add flow-root BFC isolation, vertical margin, and mobile menu scroll container
- Update brand logo kicker hover color to primary accent (cobalt-dark)
- Fix theme script hydration warning with suppressHydrationWarning
- Add favicon.ico and icon.svg to resolve root /favicon.ico 404
- Add MAM orchestration guidelines, env generation script, and templates

scripts/generate-env.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+# generate-env.sh — create a local .mam.env from the committed .mam.env.example template.
+#
+# Behaviour:
+#   - .mam.env absent            → copy .mam.env.example to .mam.env, print the path.
+#   - .mam.env present           → no-op (leaves your edits intact), exit 0.
+#   - .mam.env present --force    → overwrite .mam.env from .mam.env.example (backs up to .mam.env.bak).
+#   - --migrate-legacy           → explicitly rename existing .env to .mam.env if absent.
+#
+# Paths are resolved relative to this script (repo root = parent of scripts/),
+# so it works regardless of the caller's cwd.
+#
+# Usage: scripts/generate-env.sh [--force] [--migrate-legacy] [-h|--help]
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+SRC="$REPO_ROOT/.mam.env.example"
+DST="$REPO_ROOT/.mam.env"
+LEGACY_ENV="$REPO_ROOT/.env"
+
+FORCE=0
+MIGRATE=0
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --force) FORCE=1; shift ;;
+    --migrate-legacy) MIGRATE=1; shift ;;
+    -h|--help)
+      echo "Usage: $0 [--force] [--migrate-legacy]"
+      echo "  Create .mam.env from .mam.env.example."
+      echo "  --force           overwrites an existing .mam.env (backs up to .mam.env.bak)."
+      echo "  --migrate-legacy  explicitly renames an existing legacy .env to .mam.env."
+      exit 0 ;;
+    *) echo "ERROR: unknown arg: $1" >&2; echo "Usage: $0 [--force] [--migrate-legacy]" >&2; exit 2 ;;
+  esac
+done
+
+if [ "$MIGRATE" = "1" ]; then
+  if [ -f "$DST" ]; then
+    echo "ERROR: cannot migrate: $DST already exists." >&2
+    exit 1
+  fi
+  if [ ! -f "$LEGACY_ENV" ]; then
+    echo "ERROR: cannot migrate: legacy file $LEGACY_ENV not found." >&2
+    exit 1
+  fi
+  mv -f "$LEGACY_ENV" "$DST"
+  chmod 0600 "$DST" 2>/dev/null || true
+  echo "migrated: $LEGACY_ENV -> $DST"
+  exit 0
+fi
+
+[ -f "$SRC" ] || { echo "ERROR: template not found: $SRC" >&2; exit 1; }
+
+if [ -f "$DST" ] && [ "$FORCE" != "1" ]; then
+  echo "no-op: $DST already exists (use --force to overwrite)"
+  exit 0
+fi
+
+if [ -f "$DST" ] && [ "$FORCE" = "1" ]; then
+  cp -p "$DST" "$DST.bak"
+  echo "backed up existing .mam.env -> $DST.bak"
+fi
+
+cp "$SRC" "$DST"
+chmod 0600 "$DST" 2>/dev/null || true
+echo "created: $DST"
+echo "Next: edit $DST and fill in any secrets (look for 'replace_me')."