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.

sdk/typescript/README.md

@@ -0,0 +1,59 @@
+# @obsidian-api/sdk
+TypeScript SDK for this HTTP wrapper around the **official Obsidian CLI**.
+
+The SDK is built for Node 18+, n8n Code nodes, Prism, and other TypeScript agent harnesses.
+
+## Install locally
+```bash
+npm install /path/to/obsidian-api/sdk/typescript
+```
+
+## Usage
+```ts
+import { ObsidianCliClient } from '@obsidian-api/sdk';
+
+const obsidian = new ObsidianCliClient({
+  baseUrl: 'http://localhost:8080',
+  token: 'change-me',
+});
+
+await obsidian.create({
+  path: 'Inbox/Hello.md',
+  content: '# Hello from n8n/Prism',
+  overwrite: true,
+});
+
+const note = await obsidian.read({ path: 'Inbox/Hello.md' });
+console.log(note.stdout);
+
+const results = await obsidian.search('Hello', { format: 'json' });
+console.log(JSON.parse(results.stdout));
+```
+
+## Multiple vaults
+Use the official CLI `vault=<name>` prefix directly:
+```ts
+await obsidian.runInVault('work', 'create', 'path=Inbox/Task.md', 'content=Hello');
+```
+
+Or create a scoped client:
+```ts
+const workVault = obsidian.inVault('work');
+await workVault.create({ path: 'Inbox/Task.md', content: 'Hello', overwrite: true });
+await workVault.read({ path: 'Inbox/Task.md' });
+```
+
+You can also set a default vault in the constructor:
+```ts
+const obsidian = new ObsidianCliClient({
+  baseUrl: 'http://localhost:8080',
+  token: 'change-me',
+  vault: 'work',
+});
+```
+
+## Raw command escape hatch
+Still safe: sends an args array, not a shell command string.
+```ts
+await obsidian.runRaw('create', 'name=Scratch', 'content=Test', 'overwrite');
+```