test(live): framework fixture matrix for inject / wrap / is-generated

Five representative project shapes under tests/framework-fixtures/ that
stage into fresh tmp git repos and drive the live scripts against each:

- vite-react: tracked index.html shell + src/App.jsx
- nextjs-app: app/layout.tsx as JSX inject target
- astro: src/layouts/Layout.astro
- sveltekit: src/app.html shell + src/routes/+page.svelte
- multipage-with-generator: src/ tracked, dist/ gitignored (our own
  repo's shape); exercises the is-generated guard and
  element_not_in_source fallback

Each fixture declares its config, expected source/generated paths, and
wrap cases in fixture.json. The harness copies into tmpdir, applies
gitignore, commits, then asserts:

- inject --port lands the script tag at the correct anchor across all
  configured files
- inject --remove strips it cleanly
- is-generated classifies source vs generated paths correctly
- wrap routes to the expected source file or emits the expected
  fallback error

Plumbing + bug caught while building out the matrix:

- IMPECCABLE_LIVE_CONFIG env var so tests can point live-inject at a
  fixture-specific config.json without clobbering the harness copy.
  Backwards-compatible.
- live-wrap.mjs no longer hardcodes dist/build in its directory skip
  list. Only node_modules and .git remain universal skips; the
  isGeneratedFile check is now the sole guard for generated paths. This
  lets the includeGenerated second pass find elements in dist/ and
  report generatedMatch, which is what the multipage-with-generator
  fixture needs to exercise.

Wired into bun run test. 25 tests, 5 suites.

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

tests/framework-fixtures/vite-react/fixture.json

@@ -0,0 +1,17 @@
+{
+  "name": "Vite + React",
+  "config": {
+    "files": ["index.html"],
+    "insertBefore": "</body>",
+    "commentSyntax": "html"
+  },
+  "sourceFiles": ["index.html", "src/App.jsx"],
+  "generatedFiles": [],
+  "wrapCases": [
+    {
+      "name": "wraps hero title in source JSX",
+      "args": { "classes": "hero-title", "tag": "h1" },
+      "expectedFile": "src/App.jsx"
+    }
+  ]
+}