feat: add record-browser skill with annotation tools and vision-replay improvements

[mrrobertkent]

Summary

• New skill: Record Browser — Launch a headed Chrome browser with built-in recording and annotation tools powered by fabric.js. Includes a glassmorphism toolbar with Record/On Action modes, 6 drawing tools (Select, Pen, Line, Rectangle, Circle, Text), configurable arrowheads (plain, end, start, double), 5 AI-optimized color presets, stroke/fill controls, text formatting (4 sizes, BG/BD toggles), keyboard shortcuts, and a post-recording dialog with playback, rename, and save/close. Welcome page launches when no URL is provided.
• Vision Replay improvements — Restructured SKILL.md with cleaner XML sections, added structured intake gate with question templates, added examples/error-handling.md with common error scenarios and recovery actions, improved routing table with annotation-aware workflow detection, added entry/exit point documentation.
• Record Browser + Vision Replay integration — Recordings from Record Browser chain seamlessly into Vision Replay for AI analysis. Annotations (colored shapes drawn during recording) are automatically prioritized during frame analysis.
• Multi-agent support updated — AGENTS.md updated with Record Browser instructions matching the corrected SKILL.md workflow.
• Help skill updated — Lists both skills with accurate descriptions and current feature set.
• Test suite expanded — 41 tests covering vision-replay scripts, record-browser scripts, vendored assets, and page assets.
• Documentation updated — README.md reflects all current features, platform support, troubleshooting, and known issues.

Known Issues

• Chrome for Testing v146 "quit unexpectedly" dialog on close (cosmetic only — does not affect recording, video saving, or workflow). Tracked in Chrome for Testing v146 'quit unexpectedly' dialog on close (macOS ARM64) #5.

Pre-merge test plan

• bash tests/test-scripts.sh — 41/41 tests passing
• Launch Record Browser with no URL (welcome page loads)
• Launch Record Browser with a URL (page loads correctly)
• Record a workflow with annotations, save, verify HELIX_SAVED output
• Chain saved recording into Vision Replay analysis
• Run /helixlab:setup --check to verify dependency detection

Post-merge verification

• Run /helixlab:help — verify v1.2.0 and all 3 skills listed
• Verify plugin.json and marketplace.json versions are 1.2.0