adds devcontainer with docker

CLAUDE.md

@@ -54,6 +54,34 @@ Each stage reads the previous stage's output file. Stages are independent and ca
 - Concurrent processing with `asyncio.Semaphore(CONCURRENCY_LIMIT=1)`.
 - Cleans up intermediate WAV files after conversion.
 
+### DevContainer (`.devcontainer/`)
+
+A VS Code Dev Container enables reproducible development. Two files define it:
+
+- **`Dockerfile`** (based on `python:3.11-slim`):
+  - Installs system deps: `git`, `curl`, `ffmpeg`.
+  - Copies and installs `requirements.txt` (project root) into the container at `/app/`.
+  - Sets default env vars: `OLLAMA_URL`, `MODEL_NAME`, `PORT`, `POLL_INTERVAL`, `DATA_DIR`, `TTS_VOICE`.
+  - Creates `/app/data/audio/` for output.
+
+- **`devcontainer.json`**:
+  - Points VS Code to the Dockerfile.
+  - Forwards port `8080` (newscast API).
+  - `postCreateCommand`: runs `pip install -r requirements.txt` in the VS Code Python interpreter for IDE features (linting, completions).
+  - `remoteEnv`: overrides Dockerfile defaults with workspace-relative values (e.g., `DATA_DIR` points to `${workspaceFolder}/data`).
+  - Extensions: `ms-python.python`, `ms-python.vscode-pylance`.
+
+**Key env vars** (Dockerfile defaults, overridable via `devcontainer.json` `remoteEnv`):
+
+| Variable | Default | Description |
+|---|---|---|
+| `OLLAMA_URL` | `http://host.docker.internal:11434/api/generate` | Ollama API endpoint (use `host.docker.internal` to reach host from container) |
+| `MODEL_NAME` | `gemma4:e2b` | Ollama model identifier |
+| `PORT` | `8080` | Newscast API listen port |
+| `POLL_INTERVAL` | `21600` | API polling interval in seconds (6 hours) |
+| `DATA_DIR` | `/app/data` | Base directory for all pipeline output files |
+| `TTS_VOICE` | `af_heart` | Kokoro TTS voice |
+
 ## Common Tasks
 
 ### Add a New Pipeline Stage