feat(human-flow): AST-based scanner v2 + Friction Index rubric

Upgrade the human-flow skill (Gemini-assisted, Claude-reviewed):
- scan.mjs rewritten to AST-based (@babel/parser/traverse) with 4
  detectors: unlabeled-icon-button, tiny-target, missing-feedback-props,
  click-without-keyboard; regex fallback on parse failure.
- Objective Friction Index (Motor 3.0 / Cognitive 2.5 / Keyboard 2.5 /
  Feedback 2.0); 0-10 Human Workflow Score.
- New heuristics: State-Flow Audit, Precision Rail / Fumble Zones,
  Restraint-o-Meter (1-5) for the fancy pass.
- `fix` command DISABLED for now (advisory only): the AST generator
  reprints whole files and produces noisy diffs; agents apply surgical
  fixes from the report. To be revisited with a string-splice editor.
- Add @babel/* deps + package-lock.json.
- Memory: agy review/review-files is NOT actually read-only (wrote files
  + ran npm despite documented plan-mode) — diff after every agy review.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.claude/skills/human-flow/package.json

@@ -6,5 +6,11 @@
   "scripts": {
     "scan": "node scripts/scan.mjs",
     "fancy": "node scripts/scan.mjs --fancy"
+  },
+  "dependencies": {
+    "@babel/generator": "^7.29.7",
+    "@babel/parser": "^7.29.7",
+    "@babel/traverse": "^7.29.7",
+    "@babel/types": "^7.29.7"
   }
-}
+}