Add stop-all buttons to target sections, perf chart color reset, and TODO

- Add stop-all buttons to LED targets and KC targets section headers
  (visible only when targets are running, uses headerExtra on CardSection)
- Add reset ability to performance chart color pickers (removes custom
  color from localStorage and reverts to default)
- Remove CODEBASE_REVIEW.md
- Add prioritized TODO.md with P1/P2/P3 feature roadmap

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/js/app.js

@@ -97,6 +97,7 @@ import {
     loadTargetsTab, switchTargetSubTab,
     showTargetEditor, closeTargetEditorModal, forceCloseTargetEditorModal, saveTargetEditor,
     startTargetProcessing, stopTargetProcessing,
+    stopAllLedTargets, stopAllKCTargets,
     startTargetOverlay, stopTargetOverlay, deleteTarget,
     cloneTarget, toggleLedPreview, toggleTargetAutoStart,
     expandAllTargetSections, collapseAllTargetSections,
@@ -343,6 +344,8 @@ Object.assign(window, {
     saveTargetEditor,
     startTargetProcessing,
     stopTargetProcessing,
+    stopAllLedTargets,
+    stopAllKCTargets,
     startTargetOverlay,
     stopTargetOverlay,
     deleteTarget,