fix(studio): SSR-safe player load, captions import cleanup (#248)

* fix(studio): load @hyperframes/player lazily to support SSR

Player.tsx had a bare `import "@hyperframes/player"` at module scope. The
player package registers a class that extends HTMLElement as a side effect,
and HTMLElement doesn't exist in a Node server runtime. Any consumer that
imported from @hyperframes/studio during server-side rendering (e.g. the
Next.js App Router evaluating a client component for SSR) threw
`HTMLElement is not defined`.

Move the import inside the mount effect via dynamic `import(...)` so it
only runs in the browser, and wire up a cancellation flag and deferred
cleanup so a fast unmount doesn't leak listeners or DOM nodes.

* fix(studio): remove .js extensions from captions-internal imports

The captions module imported sibling files as `./types.js` and
`./parser.js`. That's legal ESM TypeScript, but Turbopack (and other
bundlers) refuse to resolve those specifiers against .ts files when the
package is consumed from node_modules — the rest of @hyperframes/studio
uses extensionless imports for that reason.

Align captions with the rest of the codebase so the package builds
without bundler-specific configuration in consumers.

* chore: release @hyperframes/player@0.2.7 and @hyperframes/studio@0.2.9

Ships the root-timeline resolution fix (#247), the SSR-safe player load,
and the captions import cleanup.

packages/studio/src/captions/generator.test.ts

@@ -1,7 +1,7 @@
 // @vitest-environment node
 import { describe, it, expect } from "vitest";
-import { generateCaptionHtml } from "./generator.js";
-import { buildCaptionModel, TranscriptWord } from "./parser.js";
+import { generateCaptionHtml } from "./generator";
+import { buildCaptionModel, TranscriptWord } from "./parser";
 
 // ---------------------------------------------------------------------------
 // Fixtures

packages/studio/src/captions/generator.ts

@@ -8,7 +8,7 @@ import type {
   CaptionContainerStyle,
   CaptionShadow,
   CaptionGlow,
-} from "./types.js";
+} from "./types";
 
 // ---------------------------------------------------------------------------
 // Public API

packages/studio/src/captions/parser.test.ts

@@ -1,7 +1,7 @@
 // @vitest-environment node
 import { describe, it, expect } from "vitest";
-import { extractTranscript, buildCaptionModel, TranscriptWord } from "./parser.js";
-import { DEFAULT_STYLE, DEFAULT_CONTAINER, DEFAULT_ANIMATION_SET } from "./types.js";
+import { extractTranscript, buildCaptionModel, TranscriptWord } from "./parser";
+import { DEFAULT_STYLE, DEFAULT_CONTAINER, DEFAULT_ANIMATION_SET } from "./types";
 
 // ---------------------------------------------------------------------------
 // Fixtures

packages/studio/src/captions/parser.ts

@@ -11,7 +11,7 @@ import {
   DEFAULT_STYLE,
   DEFAULT_CONTAINER,
   DEFAULT_ANIMATION_SET,
-} from "./types.js";
+} from "./types";
 
 export interface TranscriptWord {
   id?: string;