refactor: drop unused exports detected by fallow auto-fix

Run `fallow fix --auto-fixable` to remove `export` keywords from symbols
fallow's reachability analysis identifies as unused. Keeps only the cases
where the symbol is still referenced internally in its own file (so
removing `export` doesn't surface a new oxlint `no-unused-vars` error).

Result: fallow dead-code findings drop from 276 → 208 (68 fewer unused
exports), with no behavior change — each symbol is still defined and used
exactly the same way within its file.

Reverted ~20 files where fallow's auto-fix would have created cascading
"declared but never used" lint errors — those are cases where the symbol
isn't used at all, and properly cleaning them up means deleting the
declaration, not just dropping `export`. Better to land that as a
separate, narrower PR rather than mixing it into a mechanical de-export.

Also reverted four false positives where fallow missed real consumers:
- `captureCost.ts` (renderOrchestrator has two separate import blocks
  from the same module; fallow only saw the first)
- `propertyPanelHelpers.ts`, `domEditingLayers.ts` (real internal uses
  fallow's reachability missed)
- `render.ts` (functions imported via `await import()` dynamic import,
  which fallow's static analysis doesn't follow)

Test plan: bun run --filter '*' typecheck (clean), oxlint + oxfmt clean,
cli/core/studio/engine vitest suites pass (335 + 917 + 576 + 605 tests).

packages/core/src/lint/utils.ts

@@ -15,10 +15,10 @@ export type ExtractedBlock = {
   index: number;
 };
 
-export const TAG_PATTERN = /<([a-z][\w:-]*)(\s[^<>]*?)?>/gi;
+const TAG_PATTERN = /<([a-z][\w:-]*)(\s[^<>]*?)?>/gi;
 export const STYLE_BLOCK_PATTERN = /<style\b([^>]*)>([\s\S]*?)<\/style>/gi;
 export const SCRIPT_BLOCK_PATTERN = /<script\b([^>]*)>([\s\S]*?)<\/script>/gi;
-export const COMPOSITION_ID_IN_CSS_PATTERN = /\[data-composition-id=["']([^"']+)["']\]/g;
+const COMPOSITION_ID_IN_CSS_PATTERN = /\[data-composition-id=["']([^"']+)["']\]/g;
 export const TIMELINE_REGISTRY_INIT_PATTERN =
   /window\.__timelines\s*=\s*window\.__timelines\s*\|\|\s*\{\}|window\.__timelines\s*=\s*\{\}|window\.__timelines\s*\?\?=\s*\{\}/i;
 export const TIMELINE_REGISTRY_ASSIGN_PATTERN = /window\.__timelines\[[^\]]+\]\s*=/i;

packages/core/src/runtime/adapters/lottie.ts

@@ -1,6 +1,5 @@
 import type { RuntimeDeterministicAdapter } from "../types";
 import { swallow } from "../diagnostics";
-export { isLottieAnimationLoaded } from "../../lottieReadiness";
 
 /**
  * Lottie adapter for HyperFrames

packages/core/src/studio-api/helpers/waveform.ts

@@ -4,7 +4,7 @@ import { join } from "node:path";
 
 const SAMPLE_RATE = 4000;
 const PEAK_COUNT = 4000;
-export const WAVEFORM_CACHE_VERSION = "v2";
+const WAVEFORM_CACHE_VERSION = "v2";
 
 export function buildWaveformCacheKey(assetPath: string): string {
   return `${WAVEFORM_CACHE_VERSION}_${assetPath.replace(/[/\\]/g, "_")}.json`;

packages/core/src/studio-api/routes/waveform.ts

@@ -4,9 +4,6 @@ import type { Hono } from "hono";
 import type { StudioApiAdapter } from "../types.js";
 import { decodeAudioPeaks, buildWaveformCacheKey } from "../helpers/waveform.js";
 
-export { isAudioFile } from "../helpers/mime.js";
-export { generateWaveformCache } from "../helpers/waveform.js";
-
 export function registerWaveformRoutes(api: Hono, adapter: StudioApiAdapter): void {
   api.get("/projects/:id/waveform/*", async (c) => {
     const project = await adapter.resolveProject(c.req.param("id"));