PR_26171_035 remove idea board notes heading

[ToolboxAid]

Summary

• Removes the visible Notes heading from expanded Idea Board notes rows.
• Flattens the expanded row content so the notes table and Add Note action sit directly inside the expanded row, under the owning idea row.
• Updates targeted Playwright checks to verify no notes heading/header marker, no expanded-row content-stack wrapper, and immediate row adjacency.

Validation

• PASS: node --check toolbox/idea-board/index.js
• PASS: node --check tests/playwright/tools/IdeaBoardTableNotes.spec.mjs
• PASS: node --check tests/playwright/tools/ToolboxRoutePages.spec.mjs
• PASS: npx playwright test tests/playwright/tools/IdeaBoardTableNotes.spec.mjs --project=playwright --workers=1 --reporter=line
• PASS: npx playwright test tests/playwright/tools/ToolboxRoutePages.spec.mjs --project=playwright --workers=1 --reporter=line -g "Idea Board launches"
• PASS: npm run test:workspace-v2

Artifact

• tmp/PR_26171_035-idea-board-inline-notes-no-heading_delta.zip