feat(cli): add --title flag to set tab title when summoning

Add a --title <title> flag to the dispatch CLI so a summoned agent's
conversation/tab gets a human-readable title at creation time instead of the
auto-derived default (Untitled until the first message append).

The title is carried as an additive optional ChatRequest.title field (the
HTTP client-server contract), parsed + trimmed server-side in parseChatBody,
and persisted via the conversation store's setConversationTitle in the POST
/chat route BEFORE the turn starts — so the title is set atomically with
creation and before --open signals the frontend to open the tab. No second
HTTP round-trip is needed.

A whitespace-only title is treated as absent (auto-derive); a non-string
title yields HTTP 400. A title-set failure is logged but never blocks the
turn (the title is a nicety, the answer is not). The change is purely
additive — no existing behavior or assertion changes.

Verification: typecheck EXIT 0; test 2021 passed | 6 skipped | 0 failed;
check EXIT 0 (12 pre-existing warnings in untouched files).

1 files changed, 43 insertions, 0 deletions

diff --git a/packages/cli/src/args.test.ts b/packages/cli/src/args.test.ts
index e6b43cf..14c4ffc 100644
--- a/packages/cli/src/args.test.ts
+++ b/packages/cli/src/args.test.ts
@@ -216,6 +216,49 @@ describe("parseArgs", () => {
       expect(result.kind).toBe("error");
       if (result.kind === "error") expect(result.message).toContain("--workspace requires a value");
     });
+
+    it("parses --title flag", () => {
+      const result = parseArgs(["m", "--text", "x", "--title", "My Task"], { defaultServer });
+      expect(result).toEqual({
+        kind: "chat",
+        server: "http://localhost:24203",
+        modelName: "m",
+        text: "x",
+        file: undefined,
+        cwd: undefined,
+        conversationId: undefined,
+        reasoningEffort: undefined,
+        showReasoning: false,
+        open: false,
+        title: "My Task",
+      });
+    });
+
+    it("parses --title with --workspace together", () => {
+      const result = parseArgs(["m", "--text", "x", "--workspace", "ws", "--title", "T"], {
+        defaultServer,
+      });
+      expect(result.kind).toBe("chat");
+      if (result.kind === "chat") {
+        expect(result.workspaceId).toBe("ws");
+        expect(result.title).toBe("T");
+      }
+    });
+
+    it("omits title when --title is not given", () => {
+      const result = parseArgs(["m", "--text", "x"], { defaultServer });
+      expect(result.kind).toBe("chat");
+      if (result.kind === "chat") {
+        expect(result.title).toBeUndefined();
+        expect(result).not.toHaveProperty("title");
+      }
+    });
+
+    it("errors when --title has no value", () => {
+      const result = parseArgs(["m", "--text", "x", "--title"], { defaultServer });
+      expect(result.kind).toBe("error");
+      if (result.kind === "error") expect(result.message).toContain("--title requires a value");
+    });
   });
 
   describe("list", () => {