[0.83.x] Backport paired watcher matching fixes and remove micromatch

[gogulapatipavani212]

Summary

Backport the paired watcher fixes from #2000 (a77924694dd4e36c0a3e595956e322033a6c2c57) and #2024 (3865c007c592c4ab7357f95fa6ae9e6ac735a7d1) to 0.83.x. Related: #2027.

metro-file-map no longer needs micromatch to select extensions, exact basenames, and health-check prefixes. The extension matcher checks the suffix after every dot, preserving .env, .env.local, and multipart extensions such as d.ts.

The adaptation preserves this branch's NativeWatcher event handling, Flow syntax, and walker dependency. Generated TypeScript declarations are synchronized. The existing integration test now checks creation, modification, and deletion of dotfiles, multipart extensions, hidden files, and package.json in addition to ordinary JavaScript files.

This is a draft for review of the backport and release policy. It removes the metro-file-map dependency path; independent uses of micromatch elsewhere in the monorepo remain. No dependency audit policy is changed.

Changelog: [Fix] Remove metro-file-map's micromatch dependency while preserving dotfile and multipart-extension watcher events.

Test plan

Validated on macOS with Node 22.22.3 and Yarn 1.22.22:

• yarn install --frozen-lockfile
• yarn test: Flow, ESLint/Prettier, build, and all 140 test suites passed; 2,555 tests passed, 19 platform/tool-dependent tests skipped, 513 snapshots passed. This includes the real NativeWatcher and FallbackWatcher integration cases. Watchman is unavailable locally; its mocked unit tests passed.
• yarn typecheck-ts: passed.
• yarn test-smoke: passed.
• git diff --check: passed.

CLA status has not been verified; no new agreement has been accepted as part of preparing this draft.

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