feat: local SQLite test env, UI fixes, and DB migrations

- UI/UX: Refine layouts and responsive styles; fix task and timer views; update
  shared components and dashboard templates
  - Updates across `app/templates/**`, `templates/**`, `app/static/base.css`,
    and `app/static/mobile.css`
- Backend: Route cleanups and minor fixes for admin, auth, invoices, and timer
  - Touches `app/routes/admin.py`, `app/routes/auth.py`, `app/routes/api.py`,
    `app/routes/invoices.py`, `app/routes/timer.py`
- DevOps: Improve Docker setup and add local testing workflow
  - Update `Dockerfile`, `docker/start-fixed.py`
  - Add `docker-compose.local-test.yml`, `.env.local-test`, start scripts
- Docs: Update `README.md` and add `docs/LOCAL_TESTING_WITH_SQLITE.md`
- Utilities: Adjust CLI and PDF generator behavior

Database (Alembic) migrations:
- 005_add_missing_columns.py
- 006_add_logo_and_task_timestamps.py
- 007_add_invoice_and_more_settings_columns.py
- 008_align_invoices_and_settings_more.py
- 009_add_invoice_created_by.py
- 010_enforce_single_active_timer.py

BREAKING CHANGE: Only one active timer per user is now enforced.

Note: Apply database migrations after deploy (e.g., `alembic upgrade head`).

docs/LOCAL_TESTING_WITH_SQLITE.md

@@ -0,0 +1,224 @@
+# Local Testing with SQLite
+
+This document explains how to run TimeTracker locally for testing using SQLite instead of PostgreSQL.
+
+## Overview
+
+The local test environment uses:
+- **SQLite database** instead of PostgreSQL (no separate database container needed)
+- **Development mode** with debug logging enabled
+- **Local data persistence** through Docker volumes
+- **Simplified setup** for quick testing and development
+
+## Quick Start
+
+### Option 1: Using Scripts (Recommended)
+
+**Windows:**
+```cmd
+scripts\start-local-test.bat
+```
+
+**Linux/macOS:**
+```bash
+./scripts/start-local-test.sh
+```
+
+**PowerShell:**
+```powershell
+.\scripts\start-local-test.ps1
+```
+
+### Option 2: Manual Docker Compose
+
+```bash
+docker-compose -f docker-compose.local-test.yml up --build
+```
+
+## Configuration
+
+The local test environment uses these key settings:
+
+- **Database**: SQLite at `/data/timetracker.db` (persisted in Docker volume)
+- **Port**: 8080 (same as production)
+- **Environment**: Development mode with debug enabled
+- **Security**: Secure cookies disabled for local testing
+- **Logs**: Available in `./logs/` directory
+
+## Environment Variables
+
+You can override default settings using environment variables:
+
+```bash
+# Timezone
+export TZ=Europe/Brussels
+
+# Currency
+export CURRENCY=EUR
+
+# Admin users (comma-separated)
+export ADMIN_USERNAMES=admin,testuser
+
+# Secret key (change for security)
+export SECRET_KEY=your-local-test-secret-key
+
+# Start with custom settings
+docker-compose -f docker-compose.local-test.yml up --build
+```
+
+## Data Persistence
+
+- **SQLite database**: Stored in Docker volume `app_data_local_test`
+- **Uploads**: Stored in `/data/uploads` (persisted in Docker volume)
+- **Logs**: Stored in `./logs/` directory (mounted from host)
+
+## Stopping the Environment
+
+```bash
+# Stop containers
+docker-compose -f docker-compose.local-test.yml down
+
+# Stop and remove volumes (WARNING: This will delete all data)
+docker-compose -f docker-compose.local-test.yml down -v
+```
+
+## Accessing the Application
+
+Once started, the application will be available at:
+- **URL**: http://localhost:8080
+- **Health Check**: http://localhost:8080/_health
+
+## Database Management
+
+### Viewing SQLite Database
+
+You can access the SQLite database directly:
+
+```bash
+# Copy database from container to host
+docker cp timetracker-app-local-test:/data/timetracker.db ./local-db.sqlite
+
+# Use sqlite3 command line tool
+sqlite3 local-db.sqlite
+
+# Or use any SQLite browser tool
+```
+
+### Resetting Database
+
+To start with a fresh database:
+
+```bash
+# Stop and remove volumes
+docker-compose -f docker-compose.local-test.yml down -v
+
+# Start again
+docker-compose -f docker-compose.local-test.yml up --build
+```
+
+## Troubleshooting
+
+### Container Won't Start
+
+1. **Check Docker is running**:
+   ```bash
+   docker info
+   ```
+
+2. **Check port 8080 is available**:
+   ```bash
+   netstat -an | grep 8080
+   ```
+
+3. **View container logs**:
+   ```bash
+   docker-compose -f docker-compose.local-test.yml logs app
+   ```
+
+### Database Issues
+
+1. **Check database file exists**:
+   ```bash
+   docker exec timetracker-app-local-test ls -la /data/
+   ```
+
+2. **Reset database**:
+   ```bash
+   docker-compose -f docker-compose.local-test.yml down -v
+   docker-compose -f docker-compose.local-test.yml up --build
+   ```
+
+### Permission Issues
+
+The local test setup includes a custom entrypoint that automatically handles permissions. If you still encounter issues:
+
+```bash
+# Check container logs for permission errors
+docker-compose -f docker-compose.local-test.yml logs app
+
+# If needed, fix permissions manually
+docker exec timetracker-app-local-test chown -R timetracker:timetracker /data
+```
+
+### Entrypoint Issues
+
+If you encounter issues with the entrypoint script (like `su-exec: not found`), you can use the simplified entrypoint:
+
+1. **Edit docker-compose.local-test.yml** and change the entrypoint line:
+   ```yaml
+   # Change this line:
+   entrypoint: ["/app/docker/entrypoint-local-test.sh"]
+   
+   # To this:
+   entrypoint: ["/app/docker/entrypoint-local-test-simple.sh"]
+   ```
+
+2. **Restart the container**:
+   ```bash
+   docker-compose -f docker-compose.local-test.yml down
+   docker-compose -f docker-compose.local-test.yml up --build
+   ```
+
+The simplified entrypoint runs everything as root, which avoids user switching issues but is less secure (fine for local testing).
+
+### License Server Errors
+
+If you see license server 404 errors, they should be automatically disabled in the local test environment. If you still see them:
+
+1. **Verify environment variable is set**:
+   ```bash
+   docker exec timetracker-app-local-test env | grep LICENSE_SERVER_ENABLED
+   ```
+
+2. **Should show**: `LICENSE_SERVER_ENABLED=false`
+
+3. **If not set correctly, restart the container**:
+   ```bash
+   docker-compose -f docker-compose.local-test.yml restart
+   ```
+
+## Differences from Production
+
+| Feature | Local Test | Production |
+|---------|------------|------------|
+| Database | SQLite | PostgreSQL |
+| Debug Mode | Enabled | Disabled |
+| Secure Cookies | Disabled | Enabled |
+| Data Volume | `app_data_local_test` | `app_data` |
+| Container Name | `timetracker-app-local-test` | `timetracker-app` |
+
+## Development Tips
+
+1. **Hot Reload**: The development environment supports hot reloading for Python changes
+2. **Logs**: Check `./logs/timetracker.log` for detailed application logs
+3. **Database**: Use SQLite browser tools for easier database inspection
+4. **Testing**: This environment is perfect for testing new features before production deployment
+
+## Security Note
+
+⚠️ **Important**: This local test environment is configured for development only:
+- Secure cookies are disabled
+- Debug mode is enabled
+- Uses a default secret key
+
+**Never use these settings in production!**