Add multi-account OAuth, Obsidian integration, product assets, and test tooling

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

test-tool-direct.mjs

@@ -0,0 +1,12 @@
+import 'dotenv/config';
+import { handleToolCall } from './dist/tools.js';
+
+async function main() {
+  // Test via the same path the server uses
+  const result = await handleToolCall('search_messages', { q: 'test', account: 'gmail', maxResults: 3 });
+  console.log(JSON.stringify(result, null, 2));
+}
+main().catch(err => {
+  console.error('ERROR:', err.message);
+  console.error(err.stack);
+});