feat: add Obsidian CLI API service

- Add Docker image for the official Obsidian desktop app and CLI.

- Start Obsidian headlessly with Xvfb and DBus setup.

- Expose a safe structured HTTP command API without shell execution.

- Add JWT-based vault, path, and command authorization.

- Support single-vault and multi-vault container mounts.

- Add TypeScript SDK helpers for Obsidian CLI commands.

- Add n8n community node package with Obsidian operations.

- Add docs, compose config, tests, and production image workflow.

.gitignore

@@ -0,0 +1,10 @@
+obsidian_api.egg-info/
+.venv/
+__pycache__/
+.pytest_cache/
+vault/
+.env
+node_modules/
+packages/*/node_modules/
+packages/*/dist/
+sdk/typescript/dist/