feat(auth): add authentication routes and user token handling

- Implemented user authentication routes in `auth.ts` for fetching current user info and admin verification.
- Added caching mechanism for user tokens to improve performance.
- Created middleware for admin authentication.

feat(opencode): create OpenCode client route

- Added `opencode-cnb` route for creating OpenCode clients with session management.
- Integrated OpenCode SDK for client operations and session handling.

refactor(client): encapsulate OpenCode client creation

- Created a utility function `getClient` in `client.ts` to initialize OpenCode clients.

test(opencode): add tests for OpenCode routes

- Implemented test cases for OpenCode routes in `list.ts` to validate functionality.
- Created common utilities for testing in `common.ts`.

assistant/src/routes/opencode/module/client.ts

@@ -0,0 +1,8 @@
+import { createOpencodeClient } from "@opencode-ai/sdk"
+
+export const getClient = async (opts?: { baseUrl?: string }) => {
+  const client = await createOpencodeClient({
+    baseUrl: opts?.baseUrl ?? "http://localhost:4096",
+  })
+  return client;
+}