Auto-deduplicate agent shortname on join request approval

When approving an agent join request with a shortname already in use,
append a numeric suffix (e.g. "openclaw-2") instead of returning an error.

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

server/src/__tests__/agent-shortname-collision.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { hasAgentShortnameCollision } from "../services/agents.ts";
+import { hasAgentShortnameCollision, deduplicateAgentName } from "../services/agents.ts";
 
 describe("hasAgentShortnameCollision", () => {
   it("detects collisions by normalized shortname", () => {
@@ -35,3 +35,35 @@ describe("hasAgentShortnameCollision", () => {
     expect(collision).toBe(false);
   });
 });
+
+describe("deduplicateAgentName", () => {
+  it("returns original name when no collision", () => {
+    const name = deduplicateAgentName("OpenClaw", [
+      { id: "a1", name: "other-agent", status: "idle" },
+    ]);
+    expect(name).toBe("OpenClaw");
+  });
+
+  it("appends suffix when name collides", () => {
+    const name = deduplicateAgentName("OpenClaw", [
+      { id: "a1", name: "openclaw", status: "idle" },
+    ]);
+    expect(name).toBe("OpenClaw 2");
+  });
+
+  it("increments suffix until unique", () => {
+    const name = deduplicateAgentName("OpenClaw", [
+      { id: "a1", name: "openclaw", status: "idle" },
+      { id: "a2", name: "openclaw-2", status: "idle" },
+      { id: "a3", name: "openclaw-3", status: "idle" },
+    ]);
+    expect(name).toBe("OpenClaw 4");
+  });
+
+  it("ignores terminated agents for collision", () => {
+    const name = deduplicateAgentName("OpenClaw", [
+      { id: "a1", name: "openclaw", status: "terminated" },
+    ]);
+    expect(name).toBe("OpenClaw");
+  });
+});