feat: deduplicate project shortnames on create and update

Ensure unique URL-safe shortnames by appending numeric suffixes when
collisions occur. Applied during project creation, update, and company
import flows.

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

server/src/__tests__/project-shortname-resolution.test.ts

@@ -0,0 +1,45 @@
+import { describe, expect, it } from "vitest";
+import { resolveProjectNameForUniqueShortname } from "../services/projects.ts";
+
+describe("resolveProjectNameForUniqueShortname", () => {
+  it("keeps name when shortname is not used", () => {
+    const resolved = resolveProjectNameForUniqueShortname("Platform", [
+      { id: "p1", name: "Growth" },
+    ]);
+    expect(resolved).toBe("Platform");
+  });
+
+  it("appends numeric suffix when shortname collides", () => {
+    const resolved = resolveProjectNameForUniqueShortname("Growth Team", [
+      { id: "p1", name: "growth-team" },
+    ]);
+    expect(resolved).toBe("Growth Team 2");
+  });
+
+  it("increments suffix until unique", () => {
+    const resolved = resolveProjectNameForUniqueShortname("Growth Team", [
+      { id: "p1", name: "growth-team" },
+      { id: "p2", name: "growth-team-2" },
+    ]);
+    expect(resolved).toBe("Growth Team 3");
+  });
+
+  it("ignores excluded project id", () => {
+    const resolved = resolveProjectNameForUniqueShortname(
+      "Growth Team",
+      [
+        { id: "p1", name: "growth-team" },
+        { id: "p2", name: "platform" },
+      ],
+      { excludeProjectId: "p1" },
+    );
+    expect(resolved).toBe("Growth Team");
+  });
+
+  it("keeps non-normalizable names unchanged", () => {
+    const resolved = resolveProjectNameForUniqueShortname("!!!", [
+      { id: "p1", name: "growth" },
+    ]);
+    expect(resolved).toBe("!!!");
+  });
+});