Issue 4935 useTocSideBarState Type Regression

Task

• Source: GitHub issue #4935
• Title: ``useTocSideBarState now returns any instead of the state' type
• Type: bug
• Goal: restore the public @platejs/toc/react hook contract so consumers get real inference again

Plan

1. Read issue details, repo rules, relevant learnings, and current TOC hook code.
2. Add a consumer-shaped type contract test for useTocSideBarState.
3. Reproduce the regression through the new type test.
4. Remove the any seam in the hook.
5. Run package build/typecheck, type-test verification, and lint.

Findings

• Issue body points at packages/toc/src/react/hooks/useTocSideBar.ts.
• The hook currently returns : any even though the docs promise a typed object shape.
• Existing repo learning from #4895 says consumer-facing type regressions need a public-contract assertion, not just source inspection.
• Templates consume @platejs/toc, but they do not currently call useTocSideBarState; package type-tests are the tighter seam here.
• docs/solutions/patterns/critical-patterns.md does not exist in this repo, so there was no extra critical-pattern file to load.
• The cleanest regression guard in this repo is a compile-time IsAny assertion inside useTocSideBar.spec.tsx, then package-scoped build/typecheck.
• pnpm test:types still crashes with a TypeScript 6 Debug Failure, so repo-wide type-tests are not a usable verification lane for this task.
• Direct Bun execution of packages/toc/src/react/hooks/useTocSideBar.spec.tsx fails on an existing monorepo ENOENT .../node_modules/react resolution problem unrelated to this change.

Progress

• 2026-04-01: Loaded task, planning-with-files, learnings-researcher, and tdd.
• 2026-04-01: Fetched issue #4935, inspected the TOC hook, found the explicit : any, and checked relevant learnings.
• 2026-04-01: Added IsAny compile assertions to packages/toc/src/react/hooks/useTocSideBar.spec.tsx.
• 2026-04-01: Reproduced the regression with pnpm install, pnpm turbo build --filter=./packages/toc, and pnpm turbo typecheck --filter=./packages/toc; the new assertions failed while useTocSideBarState returned any.
• 2026-04-01: Removed the explicit : any from packages/toc/src/react/hooks/useTocSideBar.ts.
• 2026-04-01: Verified green with pnpm turbo build --filter=./packages/toc, pnpm turbo typecheck --filter=./packages/toc, and pnpm lint:fix.
• 2026-04-01: pnpm check is blocked by an unrelated fast-test failure in packages/dnd/src/DndPlugin.spec.tsx (ENOENT .../packages/dnd/node_modules/react), so no PR was opened from this turn.
• 2026-04-01: User asked to add a reinstall helper from ../informed; the matching sibling repo here is ../informed-fe-v3, which already had scripts/reinstall.sh.
• 2026-04-01: Root cause for the DnD failure was stale package-local node_modules/react symlinks pointing into missing root/node_modules/.bun/... targets; pnpm install alone did not repair them.
• 2026-04-01: Added tooling/scripts/reinstall.sh and exposed it as pnpm run reinstall.
• 2026-04-01: Ran pnpm run reinstall, then verified bun test packages/dnd/src/DndPlugin.spec.tsx, pnpm --filter @platejs/dnd test src/DndPlugin.spec.tsx, pnpm test, and pnpm lint:fix all pass.