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/studio/src/captions/types.ts

@@ -191,7 +191,7 @@ export const DEFAULT_CONTAINER: CaptionContainerStyle = {
   boxShadow: "none",
 };
 
-export const DEFAULT_ANIMATION: CaptionAnimation = {
+const DEFAULT_ANIMATION: CaptionAnimation = {
   preset: "fade",
   duration: 0.2,
   ease: "power2.out",

packages/studio/src/components/editor/MotionPanelFields.tsx

@@ -1,7 +1,7 @@
 import { useState, useRef, useEffect, type ReactNode } from "react";
 import { Zap } from "../../icons/SystemIcons";
 
-export const FIELD =
+const FIELD =
   "min-w-0 rounded-xl border border-neutral-800 bg-neutral-900/95 px-3 py-2 text-neutral-100 shadow-[inset_0_1px_0_rgba(255,255,255,0.03)] transition-colors focus-within:border-neutral-600";
 export const LABEL = "text-[11px] font-medium uppercase tracking-[0.18em] text-neutral-500";
 export const RESPONSIVE_GRID = "grid grid-cols-[repeat(auto-fit,minmax(118px,1fr))] gap-3";
@@ -30,7 +30,7 @@ export function parsePlainNumber(value: string): number | null {
 
 // ── CommitField ──
 
-export function CommitField({
+function CommitField({
   value,
   disabled,
   onCommit,

packages/studio/src/components/editor/domEditOverlayGestures.ts

@@ -10,7 +10,7 @@ import type { GroupOverlayItem } from "./domEditOverlayGeometry";
 export type GestureKind = "drag" | "resize" | "rotate";
 
 export const BLOCKED_MOVE_THRESHOLD_PX = 4;
-export const MIN_RESIZE_EDGE_PX = 20;
+const MIN_RESIZE_EDGE_PX = 20;
 const ROTATION_COMMIT_EPSILON_DEGREES = 0.05;
 const ROTATION_SNAP_DEGREES = 15;
 

packages/studio/src/components/editor/domEditingDom.ts

@@ -163,7 +163,7 @@ export function normalizeTimelineCompositionSource(value: string | undefined): s
 
 // ─── CSS escaping ─────────────────────────────────────────────────────────────
 
-export function escapeCssIdentifier(value: string): string {
+function escapeCssIdentifier(value: string): string {
   const css = globalThis.CSS as { escape?: (input: string) => string } | undefined;
   if (typeof css?.escape === "function") return css.escape(value);
 

packages/studio/src/components/editor/fontAssets.ts

@@ -8,7 +8,7 @@ const FONT_EXT_RE = /\.(eot|otf|ttc|ttf|woff2?)$/i;
 const FONT_STYLE_SUFFIX_RE =
   /\s+(thin|extralight|extra light|light|regular|roman|medium|semibold|semi bold|bold|extrabold|extra bold|black|italic|oblique|variable)$/i;
 
-export function cssString(value: string): string {
+function cssString(value: string): string {
   return JSON.stringify(value);
 }
 

packages/studio/src/components/editor/gradientValue.ts

@@ -370,7 +370,7 @@ function formatHex(channel: number): string {
   return channel.toString(16).padStart(2, "0");
 }
 
-export function interpolateGradientStopColor(model: GradientModel, position: number): string {
+function interpolateGradientStopColor(model: GradientModel, position: number): string {
   const clampedPosition = clamp(position, 0, 100);
   const sortedStops = [...model.stops].sort((a, b) => a.position - b.position);
   const exact = sortedStops.find((stop) => Math.abs(stop.position - clampedPosition) < 0.001);

packages/studio/src/components/editor/manualOffsetDrag.ts

@@ -256,7 +256,7 @@ export function createManualOffsetDragMember(input: {
   };
 }
 
-export function resolveManualOffsetDragMemberOffset(
+function resolveManualOffsetDragMemberOffset(
   member: ManualOffsetDragMember,
   dx: number,
   dy: number,
@@ -289,7 +289,7 @@ export function applyManualOffsetDragCommit(
   return offset;
 }
 
-export function restoreManualOffsetDragMember(member: ManualOffsetDragMember): void {
+function restoreManualOffsetDragMember(member: ManualOffsetDragMember): void {
   restoreStudioPathOffset(member.element, member.initialPathOffset);
   endStudioManualEditGesture(member.element, member.gestureToken);
 }

packages/studio/src/components/editor/propertyPanelColor.tsx

@@ -18,7 +18,7 @@ const COLOR_PICKER_SIZE = { width: 292, height: 386 };
 /*  ColorSlider                                                        */
 /* ------------------------------------------------------------------ */
 
-export function ColorSlider({
+function ColorSlider({
   label,
   value,
   min,

packages/studio/src/components/editor/propertyPanelPrimitives.tsx

@@ -1,7 +1,7 @@
 import { useCallback, useEffect, useRef, useState, type ReactNode } from "react";
 import { adjustNumericToken, FIELD, LABEL, parseNumericToken } from "./propertyPanelHelpers";
 
-export function CommitField({
+function CommitField({
   value,
   disabled,
   liveCommit,

packages/studio/src/components/editor/studioMotionOps.ts

@@ -129,7 +129,7 @@ export function buildStudioGsapPresetMotion(
 
 // ── Manifest parse/serialize ──
 
-export function parseMotionValues(value: unknown): StudioGsapMotionValues | null {
+function parseMotionValues(value: unknown): StudioGsapMotionValues | null {
   if (!value || typeof value !== "object") return null;
   const record = value as Record<string, unknown>;
   const parsed: StudioGsapMotionValues = {};

packages/studio/src/player/components/CompositionThumbnail.tsx

@@ -16,7 +16,7 @@ interface CompositionThumbnailProps {
 
 const CLIP_HEIGHT = 66;
 const THUMBNAIL_URL_VERSION = "v3";
-export const COMPOSITION_THUMBNAIL_LABEL_Z_INDEX = 10;
+const COMPOSITION_THUMBNAIL_LABEL_Z_INDEX = 10;
 
 export function buildCompositionThumbnailUrl({
   previewUrl,

packages/studio/src/player/components/timelineLayout.ts

@@ -7,7 +7,7 @@ export const TRACK_H = 72;
 export const RULER_H = 24;
 export const CLIP_Y = 3;
 export const CLIP_HANDLE_W = 18;
-export const TIMELINE_SCROLL_BUFFER = 20;
+const TIMELINE_SCROLL_BUFFER = 20;
 
 /* ── Tick generation ──────────────────────────────────────────────── */
 function getMajorTickInterval(duration: number, pixelsPerSecond?: number): number {

packages/studio/src/player/lib/playbackAdapter.ts

@@ -20,7 +20,7 @@ export function isFinitePositive(value: number): boolean {
   return Number.isFinite(value) && value > 0;
 }
 
-export function clampTime(time: number, duration: number): number {
+function clampTime(time: number, duration: number): number {
   const safeDuration = Math.max(0, Number.isFinite(duration) ? duration : 0);
   const safeTime = Math.max(0, Number.isFinite(time) ? time : 0);
   return safeDuration > 0 ? Math.min(safeTime, safeDuration) : safeTime;

packages/studio/src/player/lib/timelineElementHelpers.ts

@@ -15,7 +15,7 @@ import { isFinitePositive } from "./playbackAdapter";
 // Duration attribute helpers
 // ---------------------------------------------------------------------------
 
-export function readDurationAttribute(el: Element | null | undefined): number {
+function readDurationAttribute(el: Element | null | undefined): number {
   if (!el) return 0;
   const duration =
     Number.parseFloat(el.getAttribute("data-duration") ?? "") ||
@@ -42,7 +42,7 @@ export function readTimelineDurationFromDocument(doc: Document | null | undefine
 // DOM element type guards
 // ---------------------------------------------------------------------------
 
-export function isHtmlElement(el: Element): el is HTMLElement {
+function isHtmlElement(el: Element): el is HTMLElement {
   const HtmlElementCtor = el.ownerDocument.defaultView?.HTMLElement ?? globalThis.HTMLElement;
   return typeof HtmlElementCtor !== "undefined" && el instanceof HtmlElementCtor;
 }
@@ -113,7 +113,7 @@ export function getTimelineElementDisplayLabel(input: {
   return tag ? `${tag} clip` : "Timeline clip";
 }
 
-export const IMPLICIT_TIMELINE_LAYER_SKIP_TAGS = new Set([
+const IMPLICIT_TIMELINE_LAYER_SKIP_TAGS = new Set([
   "base",
   "link",
   "meta",
@@ -123,7 +123,7 @@ export const IMPLICIT_TIMELINE_LAYER_SKIP_TAGS = new Set([
   "template",
 ]);
 
-export function humanizeTimelineIdentifier(value: string): string {
+function humanizeTimelineIdentifier(value: string): string {
   return value
     .trim()
     .replace(/[_-]+/g, " ")
@@ -239,7 +239,7 @@ export function getTimelineElementIdentity(element: TimelineElement): string {
 // DOM node querying
 // ---------------------------------------------------------------------------
 
-export function getTimelineDomNodes(doc: Document): Element[] {
+function getTimelineDomNodes(doc: Document): Element[] {
   const rootComp = doc.querySelector("[data-composition-id]");
   return Array.from(doc.querySelectorAll("[data-start]")).filter((node) => node !== rootComp);
 }

packages/studio/src/utils/studioFontHelpers.ts

@@ -22,7 +22,7 @@ const GENERIC_FONT_FAMILIES = new Set([
   "fangsong",
 ]);
 
-export function primaryFontFamilyFromCss(value: string): string {
+function primaryFontFamilyFromCss(value: string): string {
   const first = value.split(",")[0] ?? "";
   return first.trim().replace(/^["']|["']$/g, "");
 }

packages/studio/src/utils/studioUrlState.ts

@@ -80,7 +80,7 @@ function normalizeSelection(params: URLSearchParams): StudioUrlSelectionState |
   };
 }
 
-export function defaultStudioUrlState(): StudioUrlState {
+function defaultStudioUrlState(): StudioUrlState {
   return {
     activeCompPath: null,
     currentTime: null,

packages/studio/src/utils/timelineInspector.ts

@@ -1,6 +1,6 @@
 import type { TimelineElement } from "../player";
 
-export const TIMELINE_INSPECTOR_BOUNDARY_EPSILON_SECONDS = 0.08;
+const TIMELINE_INSPECTOR_BOUNDARY_EPSILON_SECONDS = 0.08;
 
 const AUDIO_TIMELINE_TAGS = new Set(["audio", "music", "sfx", "sound", "narration"]);
 const AUDIO_SOURCE_EXT_RE = /\.(aac|flac|m4a|mp3|ogg|opus|wav)(?:[?#].*)?$/i;

packages/studio/vite.browser.ts

@@ -20,7 +20,7 @@ const CHROME_PATHS = [
   "/usr/bin/chromium-browser",
 ];
 
-export async function getSharedBrowser(): Promise<import("puppeteer-core").Browser | null> {
+async function getSharedBrowser(): Promise<import("puppeteer-core").Browser | null> {
   if (_browser?.connected) return _browser;
   if (_browserLaunchPromise) return _browserLaunchPromise;
   _browserLaunchPromise = (async () => {