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-can-edit-path-prefix/DOC_REVIEW.md

@@ -0,0 +1,12 @@
+# Doc Review: fix-can-edit-path-prefix
+
+## Summary
+No documentation updates needed. The `--can-edit` and `--scope-check` commands' external behavior is unchanged — only the internal path comparison logic was fixed.
+
+## Findings
+- README.md, AGENTS.md, and contracts/harness-integration.md document `--can-edit` and `--scope-check` usage but not the internal path comparison implementation.
+- The fix does not change any command-line interface, output format, or exit code.
+- No user-facing behavior change for valid use cases (only invalid sibling-directory bypass is now correctly rejected).
+
+## Verdict
+No doc changes required.