feat: Integrate Playwright into docker-compose

Adds Playwright service to docker-compose.yml for easier test execution
and better integration with existing database services.

## Changes

- Add `playwright` service to docker-compose.yml:
  - Uses official Playwright image (mcr.microsoft.com/playwright:v1.49.1-noble)
  - Runs as non-root user (pwuser) for security
  - Uses host networking to access dev server on localhost:3000
  - Loads environment variables from .env
  - Uses `profiles: [test]` to keep it optional
  - Mounts node_modules volume to prevent permission issues

- Update documentation in AGENTS.md:
  - Replace standalone Docker commands with docker-compose usage
  - Document two usage patterns: `docker compose run` and `--profile test`
  - Explain benefits of integrated setup

## Usage

```bash
# Start database services
docker compose up -d

# Start dev server
pnpm dev

# Run Playwright tests in Docker
docker compose run --rm playwright
```

Or with profiles:

```bash
# Run tests one-off
docker compose --profile test run --rm playwright
```

## Benefits

- Unified infrastructure setup (database + tests)
- No need for separate Dockerfile build step
- Easier for new developers to run tests
- Consistent with existing docker-compose workflow

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

AGENTS.md

@@ -123,28 +123,40 @@ These credentials should be used for all automated testing (Magnitude, Playwrigh
 
 **Playwright Docker Setup**:
 
-For consistent testing environments across users and CI/CD, use the Playwright Docker image:
+Playwright is integrated into docker-compose for consistent testing environments:
 
-1. **Build the Playwright Docker image**:
+1. **Run Playwright tests with docker-compose**:
    ```bash
-   docker build -f Dockerfile.playwright -t ponderants-playwright .
+   # Start database services
+   docker compose up -d
+
+   # Start Next.js dev server
+   pnpm dev
+
+   # Run Playwright tests in Docker (in another terminal)
+   docker compose run --rm playwright
    ```
 
-2. **Run Playwright tests in Docker**:
+2. **Alternative: Use the 'test' profile**:
    ```bash
-   docker run --rm \
-     --network=host \
-     -v $(pwd):/home/pwuser/app \
-     -e TEST_BLUESKY_HANDLE \
-     -e TEST_BLUESKY_PASSWORD \
-     ponderants-playwright
+   # Start all services including Playwright
+   docker compose --profile test up
+
+   # Or run tests one-off without keeping services up
+   docker compose --profile test run --rm playwright
    ```
 
 3. **Benefits**:
    - Non-root user execution (pwuser) for security
    - Consistent browser versions across environments
-   - Isolated test environment
-   - Ready for CI/CD integration
+   - Integrated with existing docker-compose setup
+   - Uses host networking to access dev server on localhost:3000
+   - Node modules volume prevents permission issues
+
+4. **Configuration**:
+   - Environment variables loaded from .env file
+   - Uses `network_mode: host` to access dev server
+   - Runs with `profiles: [test]` to keep it optional
 
 **CI/CD with Gitea Actions**: