feat: Add EPUB generation tool and workflow

- Introduced a new script to build an EPUB from markdown files, enhancing documentation accessibility.
- Added a GitHub Actions workflow for automated EPUB builds on version tag pushes.
- Created the initial EPUB file 'claude-howto-guide.epub' for distribution.

This update streamlines the process of creating and releasing the Claude How-To guide in EPUB format.

.github/workflows/release.yml

@@ -0,0 +1,27 @@
+name: Build and Release EPUB
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v4
+
+      - name: Build EPUB
+        run: uv run scripts/build_epub.py
+
+      - name: Create Release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: claude-howto-guide.epub
+          generate_release_notes: true