refactor(core): simplify packages/core — dead code, dedup, type safety (#1413)

- Delete unused mediaPreloader module, 5 dead RuntimeState fields,
  emitPerformanceMetric, lintScriptUrls, 5 variable type guards
- Consolidate compiler utilities: unify CSS URL regex, relative URL
  predicate, MIME map, @import regex, bulk asset rewrite delegation
- Cache extractGsapWindows per script (eliminates 2 redundant recast
  parses per lint run), share stripJsComments and script extraction
- Deduplicate GSAP parser: share serializeValue/safeJsKey, centralize
  converted-id fallback (6 sites), keyframe codegen (3 sites),
  waypoint extraction, insert-after-anchor, script hoisting
- Replace 88 bare any annotations with typed AstNode/AstPath interfaces
- Derive RuntimeBridgeControlAction from HyperframeControlAction,
  alias RuntimePickerElementInfo, share macOS font profiler
- Gate generateHyperframesStyles on includeStyles, collapse 4 GSAP
  property mutation cases into 2
- Extract magic numbers into named constants, replace 5 double casts
  with type guards and typed accessors (runtime/globals.ts),
  reduce function complexity in htmlParser and files route

packages/core/src/index.ts

@@ -53,11 +53,6 @@ export {
   isMediaElement,
   isCompositionElement,
   getDefaultStageZoom,
-  isStringVariable,
-  isNumberVariable,
-  isColorVariable,
-  isBooleanVariable,
-  isEnumVariable,
 } from "./core.types";
 
 // Templates