feat(cli): expose Studio selection through preview (#1777)

Add a small Studio selection channel so agents can ask a running preview server
for the element the user selected in Studio. This keeps the UX on the existing
npx hyperframes preview surface while giving agents a stable source file,
target selector, timeline time, and thumbnail URL for follow-up edits.

packages/studio-server/src/createStudioApi.ts

@@ -10,6 +10,7 @@ import { registerThumbnailRoutes } from "./routes/thumbnail.js";
 import { registerWaveformRoutes } from "./routes/waveform.js";
 import { registerFontRoutes } from "./routes/fonts.js";
 import { registerRegistryRoutes } from "./routes/registry.js";
+import { registerSelectionRoutes } from "./routes/selection.js";
 
 /**
  * Create a Hono sub-app with all studio API routes.
@@ -27,6 +28,7 @@ export function createStudioApi(adapter: StudioApiAdapter): Hono {
   registerLintRoutes(api, adapter);
   registerRenderRoutes(api, adapter);
   registerThumbnailRoutes(api, adapter);
+  registerSelectionRoutes(api, adapter);
   registerWaveformRoutes(api, adapter);
   registerFontRoutes(api);
   registerRegistryRoutes(api, adapter);