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/BUG_REPORT.md

@@ -0,0 +1,13 @@
+# Bug Report: fix-stale-task-mtime-proxy
+
+## Scope
+Reviewed `scripts/status.py` `_get_edit_timestamp()`, `_touch_lastedit()`, `cmd_can_edit()`, `cmd_same_session()`, `cmd_touch()`.
+
+## Findings
+No bugs found. The `.state.lastedit` mechanism correctly:
+- Is touched on ALLOWED `--can-edit` responses
+- Falls back to `.state` mtime when `.state.lastedit` doesn't exist
+- Is excluded from `NON_ARTIFACT_FILES`
+- Used consistently across `--can-edit`, `--same-session`, and `--touch`
+
+## Verdict: PASS