Add GitHub Actions CI workflow (#28)

* #24 Add implementation plan for CI workflow

* #24 Add ruff to dev dependencies

* #24 Add GitHub Actions CI workflow

Runs lint (ruff check + format) and tests (pytest with coverage)
on pull requests to develop and main branches.

* #24 Fix CI workflow: quote version specifiers, add push trigger, align deps

- Quote pip install version specifiers to prevent shell glob expansion
- Add push trigger for develop and main branches
- Align dependency versions with requirements.txt
- Add pip cache to lint job

* #24 Update plan with implementation deviations

Author: julien731

.github/workflows/ci.yml

@@ -0,0 +1,48 @@
+name: CI
+
+on:
+  push:
+    branches: [develop, main]
+  pull_request:
+    branches: [develop, main]
+
+jobs:
+  lint:
+    name: Lint & Format
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: pip
+
+      - name: Install Ruff
+        run: pip install 'ruff>=0.9.0'
+
+      - name: Ruff check
+        run: ruff check .
+
+      - name: Ruff format check
+        run: ruff format --check .
+
+  test:
+    name: Test & Coverage
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: pip
+
+      - name: Install dependencies
+        run: |
+          pip install --upgrade pip
+          pip install 'fastapi>=0.115.0' 'uvicorn[standard]>=0.34.0' 'python-multipart>=0.0.20' 'python-dotenv>=1.0.0'
+          pip install 'pytest>=8.0.0' 'pytest-asyncio>=0.24.0' 'httpx>=0.27.0' 'pytest-cov>=6.0.0'
+
+      - name: Run tests with coverage
+        run: pytest --cov --cov-report=term-missing --cov-fail-under=80

docs/plans/24-ci-workflow.md

@@ -0,0 +1,54 @@
+# Plan: CI Workflow Setup
+
+**Story**: #24
+**Spec**: docs/specs/test-framework-setup.md (US6, US7)
+**Branch**: feature/24-ci-workflow
+**Date**: 2026-03-14
+**Mode**: Standard — infrastructure config, no application code
+
+## Technical Decisions
+
+### TD-1: Dependency installation in CI
+- **Context**: requirements.txt includes whisperx (git+https) and torch, which are large and need GPU
+- **Decision**: Use a separate `requirements-ci.txt` that excludes ML dependencies, since all tests mock them
+- **Alternatives considered**: Filtering requirements.txt with grep — fragile; installing everything — slow and unnecessary
+
+### TD-2: Ruff installation
+- **Context**: Ruff is not yet in requirements.txt but pyproject.toml already configures it
+- **Decision**: Add ruff to dev dependencies in requirements.txt
+- **Alternatives considered**: Install only in CI — would force devs to install separately
+
+## Files to Create or Modify
+
+- `requirements.txt` — add ruff to dev dependencies
+- `.github/workflows/ci.yml` — GitHub Actions workflow
+
+## Approach per AC
+
+### AC 1-2: Workflow file and triggers
+Create `.github/workflows/ci.yml` triggered on PRs to develop and main
+
+### AC 3-6: CI steps
+Checkout, Python 3.12, install deps (excluding ML packages), ruff check, ruff format --check, pytest --cov with fail_under=80
+
+### AC 7: Ruff in dev dependencies
+Add ruff to requirements.txt under dev dependencies section
+
+## Commit Sequence
+
+1. Add ruff to dev dependencies
+2. Add GitHub Actions CI workflow
+
+## Risks and Trade-offs
+
+- Coverage threshold may not be met with current test suite — pyproject.toml already sets fail_under=80
+
+## Deviations from Spec
+
+- Spec mentions branch protection documentation (US7) — skipping as it's a manual GitHub settings task, not code
+
+## Deviations from Plan
+
+- Added `push` trigger for develop/main in addition to `pull_request` (architect review: direct merges would skip CI)
+- Aligned CI dependency versions with requirements.txt instead of using bare package names
+- Added pip cache to lint job for consistency with test job

requirements.txt

@@ -11,3 +11,4 @@ pytest>=8.0.0
 pytest-asyncio>=0.24.0
 httpx>=0.27.0
 pytest-cov>=6.0.0
+ruff>=0.9.0