perf(ci): skip unit coverage on PRs that cannot reach it and persist the Jest cache (#1711)

Pull requests whose changes cannot reach any Tier A test (allowlist checked against declared Tier A inputs and an AST scan of cross-project reads) skip the unit coverage suite; master pushes always run it. Jest's transform cache is persisted with actions/cache: PRs restore only, master pushes start empty and save. Paired CI runs: Tier A 9m04s cold -> 6m09s warm. Nx Cloud is intentionally not used.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/jest.config.ts

@@ -21,6 +21,10 @@ const collectCoverageFrom = [
 export default {
   ...nxPreset,
   ...angularEsmPreset,
+  // See jest.preset.js: CI persists the transform cache from this directory.
+  ...(process.env.JEST_CACHE_DIRECTORY
+    ? { cacheDirectory: process.env.JEST_CACHE_DIRECTORY }
+    : {}),
   displayName: 'web',
   setupFilesAfterEnv: ['<rootDir>/src/test-setup.ts'],
   coverageDirectory: '../../coverage/apps/web',