ci: Add DevOps quality assurance with pre-commit hooks and GitHub Actions

- Add pre-commit hooks: Ruff lint/format, Bandit security scan, YAML/TOML validation
- Add GitHub Actions CI workflow: lint, security, test, and build jobs
- Configure Ruff and Bandit in pyproject.toml
- Add pytest test suite for build_epub.py (25 tests)
- Fix code issues: exception chaining, httpx timeout, formatting
- Add requirements.txt and requirements-dev.txt

scripts/README.md

@@ -0,0 +1,115 @@
+# EPUB Builder Script
+
+Build an EPUB ebook from the Claude How-To markdown files.
+
+## Features
+
+- Organizes chapters by folder structure (01-slash-commands, 02-memory, etc.)
+- Renders Mermaid diagrams as PNG images via Kroki.io API
+- Async concurrent fetching - renders all diagrams in parallel
+- Generates a cover image from the project logo
+- Converts internal markdown links to EPUB chapter references
+- Strict error mode - fails if any diagram cannot be rendered
+
+## Requirements
+
+- Python 3.10+
+- [uv](https://github.com/astral-sh/uv)
+- Internet connection for Mermaid diagram rendering
+
+## Quick Start
+
+```bash
+# Simplest way - uv handles everything
+uv run scripts/build_epub.py
+```
+
+## Development Setup
+
+```bash
+# Create virtual environment
+uv venv
+
+# Activate and install dependencies
+source .venv/bin/activate
+uv pip install -r requirements-dev.txt
+
+# Run tests
+pytest scripts/tests/ -v
+
+# Run the script
+python scripts/build_epub.py
+```
+
+## Command-Line Options
+
+```
+usage: build_epub.py [-h] [--root ROOT] [--output OUTPUT] [--verbose]
+                     [--timeout TIMEOUT] [--max-concurrent MAX_CONCURRENT]
+
+options:
+  -h, --help            show this help message and exit
+  --root, -r ROOT       Root directory (default: repo root)
+  --output, -o OUTPUT   Output path (default: claude-howto-guide.epub)
+  --verbose, -v         Enable verbose logging
+  --timeout TIMEOUT     API timeout in seconds (default: 30)
+  --max-concurrent N    Max concurrent requests (default: 10)
+```
+
+## Examples
+
+```bash
+# Build with verbose output
+uv run scripts/build_epub.py --verbose
+
+# Custom output location
+uv run scripts/build_epub.py --output ~/Desktop/claude-guide.epub
+
+# Limit concurrent requests (if rate-limited)
+uv run scripts/build_epub.py --max-concurrent 5
+```
+
+## Output
+
+Creates `claude-howto-guide.epub` in the repository root directory.
+
+The EPUB includes:
+- Cover image with project logo
+- Table of contents with nested sections
+- All markdown content converted to EPUB-compatible HTML
+- Mermaid diagrams rendered as PNG images
+
+## Running Tests
+
+```bash
+# With virtual environment
+source .venv/bin/activate
+pytest scripts/tests/ -v
+
+# Or with uv directly
+uv run --with pytest --with pytest-asyncio \
+    --with ebooklib --with markdown --with beautifulsoup4 \
+    --with httpx --with pillow --with tenacity \
+    pytest scripts/tests/ -v
+```
+
+## Dependencies
+
+Managed via PEP 723 inline script metadata:
+
+| Package | Purpose |
+|---------|---------|
+| `ebooklib` | EPUB generation |
+| `markdown` | Markdown to HTML conversion |
+| `beautifulsoup4` | HTML parsing |
+| `httpx` | Async HTTP client |
+| `pillow` | Cover image generation |
+| `tenacity` | Retry logic |
+
+## Troubleshooting
+
+**Build fails with network error**: Check internet connectivity and Kroki.io status. Try `--timeout 60`.
+
+**Rate limiting**: Reduce concurrent requests with `--max-concurrent 3`.
+
+**Missing logo**: The script generates a text-only cover if `claude-howto-logo.png` is not found.