feat: v0.2.0 — Groups (@group routing, roles, wizard)

Phase A of the claudemesh spec. Peers can now join named groups
with roles, and messages route to @group targets.

Broker:
- @group routing in fan-out (matches peer group membership)
- @all alias for broadcast
- join_group/leave_group WS messages + DB persistence
- list_peers returns group metadata
- drainForMember matches @group targetSpecs in SQL

CLI:
- join_group/leave_group MCP tools
- send_message supports @group targets
- list_peers shows group membership
- PeerInfo includes groups array
- Peer name cache for push notifications

Launch:
- --role flag (optional peer role)
- --groups flag (comma-separated, e.g. "frontend:lead,reviewers")
- Interactive wizard for role + groups when flags omitted
- Groups written to session config for broker hello

Spec: SPEC.md added with full v0.2 vision (groups, state, memory)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/cli/src/ws/client.ts

@@ -31,6 +31,7 @@ export interface PeerInfo {
   displayName: string;
   status: string;
   summary: string | null;
+  groups: Array<{ name: string; role?: string }>;
   sessionId: string;
   connectedAt: string;
 }
@@ -312,6 +313,18 @@ export class BrokerClient {
     this.ws.send(JSON.stringify({ type: "set_summary", summary }));
   }
 
+  /** Join a group with an optional role. */
+  async joinGroup(name: string, role?: string): Promise<void> {
+    if (!this.ws || this.ws.readyState !== this.ws.OPEN) return;
+    this.ws.send(JSON.stringify({ type: "join_group", name, role }));
+  }
+
+  /** Leave a group. */
+  async leaveGroup(name: string): Promise<void> {
+    if (!this.ws || this.ws.readyState !== this.ws.OPEN) return;
+    this.ws.send(JSON.stringify({ type: "leave_group", name }));
+  }
+
   close(): void {
     this.closed = true;
     if (this.helloTimer) clearTimeout(this.helloTimer);