feat(compiler): add @videojs/compiler package

Introduce the build-time compiler for constrained-JSX skins, rebased onto
current main as a clean, additive package. Provides:

- core pipeline: parse, compile, generate, JSX runtime, define-component
- transforms: import rewriting, replace/wrap, drop-unused locals/imports
- matchers + react lowering (add-prop, child-as-prop)
- styles className analyzer
- tailwind subsystem: design-system loader, decompose, evaluator,
  deriveClassName, emitCss, tailwindPlugin (three targets)

Self-contained: the integration smoke test now reads a vendored skin
fixture instead of the skins package, so the compiler builds and tests
green independently. 158 tests pass.

Wiring: register the project reference (tsconfig), commitlint scope,
CI test-matrix entry, and lockfile entries (lightningcss, tailwindcss).

The skin migration that consumes this compiler is parked separately —
its token refactor conflicts with skin work that landed on main; see the
follow-up commit and .claude/plans/compiler-rebase-audit.md.

commitlint.config.js

@@ -18,6 +18,7 @@ export default {
         'ci',
         'claude',
         'cli',
+        'compiler',
         'core',
         'design',
         'element',