fix(lint): promote rules to errors with registry exemptions and false-positive fixes (#1495)

* fix(lint): promote rules to errors with registry exemptions and false-positive fixes

- Export isRegistrySourceFile/isRegistryInstalledFile from composition.ts
- Add registry exemptions to google_fonts_import and font_family_without_font_face
- Add registry exemption to requestanimationframe_in_composition
- Fix timed_element_missing_clip_class: data-track-index alone no longer triggers
- Fix caption_transcript_parse_error: balanced-bracket scanner replaces non-greedy regex
- Fix missing_timeline_registry: skips sub-compositions and template-wrapped files
- Fix scene_layer_missing_visibility_kill: strip JS comments before pattern matching
- Fix gsap_css_transform_conflict: exempt from() alongside fromTo()
- Fix gsap_from_opacity_noop: only fires when opacity value is actually 0
- Add regression test for data-track-index-only elements

* test(lint): add regression tests for false-positive fixes

Covers the 7 missing negative-case assertions flagged in PR review:
- registry marker suppresses google_fonts_import + font_family_without_font_face
- registry marker suppresses requestanimationframe_in_composition
- isSubComposition suppresses missing_timeline_registry
- scene_layer_missing_visibility_kill: fires, commented-kill fires, real kill suppresses
- gsap_css_transform_conflict: from() exempt alongside fromTo()
- gsap_from_opacity_noop: non-zero opacity (e.g. 0.5) is a valid reveal, not a noop

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(examples): fix warm-grain template to pass promoted lint rules

- index.html: remove undeclared "Lexend" from font-family stack
- intro.html: replace Google Fonts @import with bundled Inter font
- captions.html: quote TRANSCRIPT keys for valid JSON + use Inter font

Fixes CLI smoke CI failure after google_fonts_import, font_family_without_font_face,
and caption_transcript_parse_error were promoted from warning to error.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(cli): resolve warm-grain from repo registry in dev mode + bundle at build

getStaticTemplateDir now falls back to registry/examples/<id> in dev mode
so CI smoke tests use the PR-branch copy instead of fetching from main.
build-copy.mjs copies warm-grain to dist/templates/warm-grain at build time
so packed CLIs can scaffold it offline.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(examples): remove trailing comma from warm-grain TRANSCRIPT array

JSON.parse rejects trailing commas (valid JS, invalid JSON).
caption_transcript_parse_error was still firing because of the comma
on the last entry after quoting all keys.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

registry/examples/warm-grain/compositions/intro.html

@@ -8,9 +8,6 @@
     </div>
 
     <style>
-      /* Import a rounded humanist sans-serif font */
-      @import url("https://fonts.googleapis.com/css2?family=Outfit:wght@400;600&display=swap");
-
       [data-composition-id="intro"] .container {
         width: 100%;
         height: 100%;
@@ -18,7 +15,7 @@
         justify-content: flex-start; /* Align to left for speaker card */
         align-items: center;
         padding-left: 5%;
-        font-family: "Outfit", sans-serif;
+        font-family: "Inter", sans-serif;
         background: transparent;
       }