Refactor Claude Code settings to use template pattern

- Create .claude/settings.json as project-wide template
- Untrack .claude/settings.local.json for local overrides
- Add .claude/settings.local.json to .gitignore
- Add .claude/README.md documenting the setup

This allows:
- Project defaults versioned in git
- Local customization without conflicts
- Clean separation of shared vs personal settings

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

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

.claude/settings.json

@@ -0,0 +1,9 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(python3:*)"
+    ],
+    "deny": []
+  },
+  "enableAllProjectMcpServers": false
+}