Fix 10 audit bugs: path prefix matching, verdict parsing, CORS, stale-task detection, phase mapping

Batch 1 (High severity):
- Bug 1: --audit cat3 now checks .automaton/tasks/ paths
- Bug 4: Verdict PASS/FAIL uses structured ## Status: line parsing
- Bug 5: register-guards.sh checks .json/.jsonc, writes plugin key, strips comments
- Bug 7: --can-edit/--scope-check path prefix uses os.sep boundary

Batch 2 (Medium/Low severity):
- Bug 2: migrate-project.sh find command parentheses for -prune binding
- Bug 3: vram_detect model prefix matching with known-suffix whitelist
- Bug 6: dashboard reads .state file before artifact heuristic fallback
- Bug 8: removed wildcard CORS, added security headers (nosniff, DENY)
- Bug 9: stale-task detection uses .state.lastedit instead of .state mtime
- Bug 10: TEST_PLAN.md maps to test_design (was implement)

249 tests pass (up from 235). All 10 tasks driven through full workflow to completion.

tasks/fix-stale-task-mtime-proxy/CODE_REVIEW.md

@@ -0,0 +1,22 @@
+# Code Review: fix-stale-task-mtime-proxy
+
+## Reviewed Files
+- `scripts/status.py` (`_get_edit_timestamp()`, `_touch_lastedit()`, `cmd_can_edit()`, `cmd_same_session()`, `cmd_touch()`, `NON_ARTIFACT_FILES`)
+
+## Changes
+1. Added `.state.lastedit` file as the stale-task timer source
+2. `_touch_lastedit()` called on ALLOWED `--can-edit` responses
+3. `_get_edit_timestamp()` reads `.state.lastedit` with fallback to `.state` mtime
+4. Added staleness check to single-task `--can-edit --task` path
+5. `--touch` now touches `.state.lastedit` instead of `.state`
+
+## Analysis
+- **Correctness**: Using `.state.lastedit` (touched on actual edit activity) is a better proxy for staleness than `.state` mtime (which only reflects phase transitions)
+- **Backward compatibility**: Falls back to `.state` mtime when `.state.lastedit` doesn't exist
+- **Non-artifact**: `.state.lastedit` correctly added to `NON_ARTIFACT_FILES` to avoid being treated as a phase artifact
+- **Single-task path**: Adding staleness check to `--can-edit --task` makes enforcement consistent across both code paths
+- **`--touch` command**: Updated to touch `.state.lastedit` — consistent with the new activity tracking model
+
+## Verdict: PASS
+
+The fix is well-structured, maintains backward compatibility, and correctly addresses the mtime proxy issue. Tests cover creation, staleness detection, and fallback behavior.