Graph editor: unified card colors, keyboard focus, color picker button

- Unified graph node colors with card color system (shared localStorage)
- Added color picker palette button to node overlay toolbar
- Auto-focus graph container for keyboard shortcuts to work immediately
- Trap Tab key to prevent focus escaping to footer
- Added mandatory bundle rebuild note to CLAUDE.md files

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -96,7 +96,13 @@ ast-index update                          # Incremental update after file change
 
 **Whenever server-side Python code is modified** (any file under `/server/src/` **excluding** `/server/src/wled_controller/static/`), **automatically restart the server** so the changes take effect immediately. Do NOT wait for the user to ask for a restart.
 
-**No restart needed for frontend-only changes.** Files under `/server/src/wled_controller/static/` (HTML, JS, CSS, JSON locale files) are served directly by FastAPI's static file handler — changes take effect on the next browser page refresh without restarting the server.
+**No restart needed for frontend-only changes** — but you **MUST rebuild the bundle**. The browser loads the esbuild bundle (`static/dist/app.bundle.js`, `static/dist/app.bundle.css`), NOT the source files. After ANY change to frontend files (JS, CSS under `/server/src/wled_controller/static/`), run:
+
+```bash
+cd server && npm run build
+```
+
+Without this step, changes will NOT take effect. No server restart is needed — just rebuild and refresh the browser.
 
 ### Restart procedure
 
@@ -136,6 +142,10 @@ Use `TODO.md` in the project root as the primary task tracker. **Do NOT use the
 - **When a task is fully done**: mark it `- [x]` and leave it for the user to clean up
 - **When the user requests a new feature/fix**: add it to the appropriate section with a priority tag
 
+## Documentation Lookup
+
+**Use context7 MCP tools for library/framework documentation lookups.** When you need to check API signatures, usage patterns, or current behavior of external libraries (e.g., FastAPI, OpenCV, Pydantic, yt-dlp), use `mcp__plugin_context7_context7__resolve-library-id` to find the library, then `mcp__plugin_context7_context7__query-docs` to fetch up-to-date docs. This avoids relying on potentially outdated training data.
+
 ## General Guidelines
 
 - Always test changes before marking as complete