docs, ci, test: README for gRPC, Dockerfile, CI pipeline, HTTP sink tests

- README: updated for gRPC API, Docker deployment, project structure
- Dockerfile: multi-stage build for containerized deployment
- CI: GitHub Actions workflow for ruff lint + pytest on push/PR
- tests: HTTP sink end-to-end tests (forwarding, 404, delivery)
- tests: comprehensive smoke test exercising all 10 gRPC endpoints

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: CI
+
+on:
+  push:
+    branches: [main, dev]
+  pull_request:
+    branches: [main]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+      - name: Install uv
+        run: pip install uv --no-cache-dir
+      - name: Install dependencies
+        run: uv sync --extra dev
+      - name: Ruff check
+        run: uv run ruff check src/ tests/
+      - name: Ruff format
+        run: uv run ruff format --check src/ tests/
+
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+      - name: Install uv
+        run: pip install uv --no-cache-dir
+      - name: Install dependencies
+        run: uv sync --extra dev
+      - name: Run tests
+        run: uv run pytest tests/ -v