feat(webclaw): add table block workbench with csv + prompt insertion

[austinlaw076]

Summary

This PR adds a new Table Block workbench feature in WebClaw chat, with inline editing and prompt integration, while preserving existing send/history/stream behavior.

What’s included

• New block type: table (columns + rows)
• Inline editable table UI:
  • Header rename
  • Cell click-to-edit
  • Enter to commit
  • Tab / Shift+Tab navigation across editable targets
• Table operations:
  • Add/remove row
  • Add/remove column (guard: cannot remove last column)
• Actions per block:
  • Copy Markdown
  • Insert to Prompt
  • CSV import/export:
    • Paste CSV + apply import
    • Copy CSV
    • Download CSV
• Per-session persistence via Zustand persist (localStorage)

Technical Notes

• Followed existing architecture and UI primitives:
  • React + Tailwind + existing Button/layout patterns
  • Zustand persistent store
  • Existing composer flow reused for prompt insertion (appendToPrompt)
• No protocol changes:
  • No changes to Gateway WS/RPC stream contract
  • Existing chat send/history/stream flow remains intact
• Added a dedicated dev route for browser E2E verification:
  • /dev/table-block

Files Changed

• apps/webclaw/src/screens/chat/chat-screen.tsx
• apps/webclaw/src/screens/chat/components/chat-composer.tsx
• apps/webclaw/src/screens/chat/hooks/use-chat-measurements.ts
• apps/webclaw/src/screens/chat/components/chat-workbench.tsx (new)
• apps/webclaw/src/screens/chat/components/table-block.tsx (new)
• apps/webclaw/src/screens/chat/hooks/use-table-workbench-blocks.ts (new)
• apps/webclaw/src/screens/chat/table-block-utils.ts (new)
• apps/webclaw/src/screens/chat/table-block-state-utils.ts (new)
• apps/webclaw/src/routes/dev.table-block.tsx (new)
• apps/webclaw/e2e/table-block.spec.ts (new)
• apps/webclaw/playwright.config.ts (new)
• apps/webclaw/vitest.config.ts (new)
• apps/webclaw/src/screens/chat/table-block-utils.test.ts (new)
• apps/webclaw/src/screens/chat/table-block-state-utils.test.ts (new)
• apps/webclaw/package.json
• apps/webclaw/src/routeTree.gen.ts
• pnpm-lock.yaml

Validation / Test Evidence

• Unit tests:
  • pnpm -C apps/webclaw test
  • Result: 3 files, 12 tests passed
• Browser E2E (Playwright):
  • pnpm -C apps/webclaw test:e2e
  • Result: 1 passed
  • Coverage:
    • Add table block
    • Cell edit + commit
    • CSV import
    • Insert to prompt
    • Refresh persistence check
• Build:
  • pnpm -C apps/webclaw build
  • Result: passed

DoD Mapping

• 10x10 edit smoothness: lightweight inline editor with keyboard navigation implemented (MVP scope)
• Markdown serialization correctness: covered by unit tests (table-block-utils.test.ts)
• Persistence after refresh: verified in Playwright E2E

Edge Cases Handled

• Empty/invalid CSV import -> user-visible error
• Trailing empty CSV lines tolerated
• Quoted CSV fields, commas, newlines, escaped quotes supported
• Prevent removing the final remaining column
• Empty rows state renders safely with guidance text