feat: add studio roadmap and streaming cleanup

.env.example

@@ -0,0 +1,10 @@
+# Copy to .env.local and fill in values
+
+# URL of the Python TTS server (used by Next.js API routes)
+VIBEVOICE_SERVER_URL=http://localhost:8000
+
+# HuggingFace token — required if the model repo is private or gated
+HF_TOKEN=
+
+# Override the HuggingFace model cache directory (optional)
+# HF_HOME=/path/to/hf-cache