Table Multi-Cell Selection Debug

Goal

Fix the /docs/table multi-cell selection runtime error:

Unable to find the path for Slate node: {"text":""}

Status

• Phase 1: Gather prior learnings and reproduce the failure — completed
• Phase 2: Trace the owning table-selection seam — completed
• Phase 3: Add regression coverage and implement the fix — completed
• Phase 4: Verify in tests and browser — completed

Findings

• The failure is reported on the local docs route http://localhost:3002/docs/table during multi-cell selection.
• A prior learning at .claude/docs/solutions/ui-bugs/2026-03-27-version-history-demo-must-clone-snapshots-per-editor.md documents the same Slate error when multiple editor surfaces share the same Slate node graph.
• The currently captured terminal output is stale and still shows the older local .bun parse failure; the docs dev server is not currently running.
• Browser repro is deterministic: dragging from the Heading cell into the lower-right cells of the first table raises Unable to find the path for Slate node: {"text":"Heading","bold":true}.
• /docs/table mounts two editors that both start from the same static tableValue graph:
  • the generic table-demo through Demo + DEMO_VALUES.table
  • the disable-merge example through table-nomerge-demo
• The table package itself was a red herring here. The docs examples were sharing the same Slate nodes across two mounted editors on one page.
• A targeted red test path with bun test is currently blocked by the local node_modules/.bun/is-hotkey parse corruption, which is separate from this table bug.

Progress Log

• Reloaded task/debug/browser/test/planning skills for this bug.
• Searched local learnings and code for table, multi-cell, and the exact Slate error.
• Started a dedicated plan file for this bug.
• Reproduced the browser crash on /docs/table with browser-use by dragging a multi-cell selection in the first table demo.
• Added createDemoValueSnapshot and switched both mounted table demos to pass cloned initial values into usePlateEditor.
• Cleaned non-versioned local env after the .bun mirror reintroduced the is-hotkey parse failure during verification, then reinstalled with pnpm install.
• Verified the regression test passes, apps/www typechecks cleanly, pnpm lint:fix passes, and the fresh /docs/table browser repro no longer throws page errors.

Errors

• bun test apps/www/src/registry/examples/values/demo-values.spec.tsx was initially blocked locally by node_modules/.bun/[email protected]/node_modules/is-hotkey/lib/index.js:251:30 Unexpected end of file.
• Cleaning node_modules, apps/www/.next, apps/www/.contentlayer, and .turbo, then rerunning pnpm install, resolved the local env corruption and unblocked verification.