feat: migrate to OpenCode SDK v2

Update all import statements to use @opencode-ai/sdk/v2
Modify Vite configurations to alias new SDK path
Update API client method signatures for SDK v2 compatibility

packages/ui/src/hooks/useSessionAutoCleanup.ts

@@ -1,5 +1,5 @@
 import React from 'react';
-import type { Session } from '@opencode-ai/sdk';
+import type { Session } from '@opencode-ai/sdk/v2';
 import { useSessionStore } from '@/stores/useSessionStore';
 import { useUIStore } from '@/stores/useUIStore';