Initial commit: scheduler service extraction from portainer-core

Extracted standalone scheduler service with:
- FastAPI REST API for task management
- APScheduler-based task execution
- PostgreSQL persistence
- Docker container support
- Gitea Actions CI/CD workflow

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,26 @@
+FROM python:3.12-slim
+
+WORKDIR /app
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y \
+    git ssh postgresql-client curl docker.io \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install Python dependencies
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy application
+COPY src/ ./src/
+COPY setup_database.sql .
+
+# Configure git
+RUN git config --global user.name "The Librarian" && \
+    git config --global user.email "librarian@schweitz.net"
+
+ENV PYTHONPATH=/app
+
+EXPOSE 8090
+
+CMD ["uvicorn", "src.main:app", "--host", "0.0.0.0", "--port", "8090", "--workers", "1"]