chore(sdk): remove orphaned @hanzo/ai AgentKit copy from the extension

The extension's packages/ai was a duplicate 'AgentKit with MCP' (canonical home:
hanzoai/ai) that squatted the @hanzo/ai name and collided with the published AI
client. Nothing consumes it anymore (all 16 adapters resolve @hanzo/ai to the
published 0.2.0 client from npm; no @hanzo/ai/server|react subpath imports; not
in the release publish). Removing it makes @hanzo/ai in the workspace
unambiguously the AI client.

Taxonomy (per direction): @hanzo/ai = AI client · @hanzo/agent = Agent SDK ·
@hanzo/ui = all v8 components (hanzoai/ui, agent UI → @hanzo/ui/agent) ·
@hanzo/gui = v8 framework (hanzoai/gui, Tauri+Tamagui unified). Removed the
@hanzo/ai CI test step. github 84 + slack 68 still green.

.github/workflows/ci.yml

@@ -32,8 +32,6 @@ jobs:
     - name: Test ACI package
       run: pnpm --filter @hanzo/aci test
 
-    - name: Test AI package
-      run: pnpm --filter @hanzo/ai test
 
     - name: Test auth core
       run: pnpm --filter @hanzo/auth test