feat(rescript): port stale/{scanner,react} packages from TS to ReScript

Per the ReScript-and-Deno language policy in .claude/CLAUDE.md.

- @accessibility-everywhere/react: Button + Modal (forwardRef, focus trap, portal,
  WCAG-compliant ARIA) with hand-rolled DOM FFI; React.useId replaces @reach/auto-id.
- @accessibility-everywhere/scanner: Scanner module with typed FFI to puppeteer/
  playwright/axe-core/fs. Method bodies preserved as TODOs to mirror the TS stubs.
- Per-package rescript.json with esmodule output, in-source .mjs.
- Root rescript.json stub (pointed at non-existent src/) removed.
- gitignore extended for nested ReScript build dirs.

Both packages compile cleanly with rescript@11. Remaining TS to port:
core/arangodb (409 LOC), cli, github-action, monitoring-api.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.gitignore

@@ -40,6 +40,10 @@ erl_crash.dump
 # ReScript
 /lib/bs/
 /.bsb.lock
+**/lib/bs/
+**/lib/ocaml/
+**/.bsb.lock
+**/.merlin
 
 # Python (SaltStack only)
 __pycache__/