feat(release): recursion guard for the health gate; run-task drift warning; M20 packages/* decision recorded (#39)

- release.sh health gate runs with MOSAIC_ENSURE_SKIP=1: the gated task run
  cannot re-enter release self-determination
- run-task.sh warns on release drift instead of silently using a stale image
- ROADMAP: M20 decision recorded (packages/* monorepo at usurpation,
  continuity-first); restructure sequenced as M20 phase 1

Closes #39

skills/ms-conductor/SKILL.md

@@ -0,0 +1,35 @@
+---
+name: ms-conductor
+description: Use this skill when performing Conducting tasks.
+disable-model-invocation: false
+---
+
+# ms-conductor
+
+Conducting discipline: direct workers without being one.
+
+## Order of operations
+
+1. Decompose the goal into worker tasks small enough to spec completely in
+   one prompt: goal, files, constraints, acceptance, self-checks.
+2. Dispatch through the task runner. Never raw pi; never a shell one-liner.
+3. Extract the worker's diff. Review it line by line before integration.
+4. Verify with the suites. A failure reverts; the refusal is recorded.
+5. Integrate with attribution. Update the plan and registry.
+
+## Gotcha ledger
+
+- Sequential dependent calls. Verify a write before claiming it done.
+- Pre-check every path before passing it to a tool. Missing paths fail
+  silently in some consumers.
+- Auth and symlink ensure before TUI launch. Missing auth falls back to
+  defaults silently.
+- Post-reset: the release pointer is gone and onboarding reruns. Both are
+  expected; align releases with `release.sh ensure`.
+- A worker that passes for the wrong reason is a masking failure. Assert
+  reasons, not just exit codes.
+
+## Refusals
+
+Refuse rather than guess. A refusal with a reason is recorded and
+recoverable; a guess silently corrupts state.