Fix 11 automation gaps: dead-end phases, autopilot runtime, guard plugin, status.py bugs, Category 3 audit

- Fix decomposition:approved and human_intervention dead-end phases
- Add scripts/autopilot.py: real drive_all() implementation
- Fix guard plugin: throw Error instead of injecting user messages
- Fix status.py: double continue, _require_state, --list-states
- Add Category 3 (git-based modification) audit
- Add Category 5 (stuck-task detection) audit
- All 206 tests pass

tasks/fix-guard-plugin-derailment/IMPLEMENTATION.md

@@ -0,0 +1,10 @@
+# IMPLEMENTATION.md — Fix Guard Plugin Derailment
+
+## Changes Made
+- `plugins/automaton-guard/plugin.ts:60-65`: Replaced `client.chat()` injection with `throw new Error()`
+
+## How It Works
+- When an edit is blocked, the guard now throws an error instead of injecting synthetic user messages
+- This prevents derailing the agent's context mid-operation
+- The harness handles the error cleanly without contaminating message history
+- The error message still includes actionable instructions for creating/transitioning tasks