feat(concurrency): loading-ring for queued chats (CR-13 consumed)

Backend shipped "queued" ConversationStatus (additive to [email protected]): when a
request blocks on a concurrency slot, conversation.statusChanged broadcasts
"queued" (broadcast-only, never persisted); "active" on slot grant.

FE consumes it:
- WS parser (adapters/ws/logic.ts): accepts "queued" in the status set.
- Store handler: "queued" updates the status map + opens a tab for a new
  cross-device queued conversation (like "active").
- TabList: status === "queued" -> loading-ring (spinner, aria-label "Queued");
  "active" -> loading-dots (unchanged).
- Composer: status type widened to ComposerStatus (idle|running|queued|error),
  exported from features/chat. "queued" -> a loading-ring status icon +
  placeholder "Queued for a slot…"; behaves like "running" for the send
  button (steer/stop — the turn is in flight, just waiting for a slot).
- App.svelte: composerStatus derived (error > queued > running > idle) —
  conversationStatus === "queued" wins over generating so the corner shows a
  ring during the wait (turn-start fires before the slot is granted, so
  generating is already true while status === "queued").
- Re-mirrored .dispatch/wire.reference.md (ConversationStatus widened + header).

Tests: WS parser accepts queued; store handler sets status + opens a cross-device
tab + transitions queued->active->idle; TabList renders a ring for queued + dots
for active. typecheck 0/0, 925 tests green (x2), biome clean, build OK.
backend-handoff.md CR-13 marked RESOLVED.

2 files changed, 21 insertions, 1 deletions

diff --git a/src/adapters/ws/logic.test.ts b/src/adapters/ws/logic.test.ts
index 113a731..dd2b773 100644
--- a/src/adapters/ws/logic.test.ts
+++ b/src/adapters/ws/logic.test.ts
@@ -283,6 +283,21 @@ describe("parseServerMessage", () => {
     });
   });
 
+  it("accepts the `queued` status (CR-13 — waiting for a concurrency slot)", () => {
+    const data = JSON.stringify({
+      type: "conversation.statusChanged",
+      conversationId: "c1",
+      status: "queued",
+      workspaceId: "w1",
+    });
+    expect(parseServerMessage(data)).toEqual({
+      type: "conversation.statusChanged",
+      conversationId: "c1",
+      status: "queued",
+      workspaceId: "w1",
+    });
+  });
+
   it("returns null for conversation.statusChanged with missing workspaceId", () => {
     expect(
       parseServerMessage(
diff --git a/src/adapters/ws/logic.ts b/src/adapters/ws/logic.ts
index ba3e7ee..03ef763 100644
--- a/src/adapters/ws/logic.ts
+++ b/src/adapters/ws/logic.ts
@@ -126,7 +126,12 @@ export function parseServerMessage(data: string): WsServerMessage | null {
     case "conversation.statusChanged": {
       if (typeof parsed.conversationId !== "string") return null;
       if (typeof parsed.status !== "string") return null;
-      if (parsed.status !== "active" && parsed.status !== "idle" && parsed.status !== "closed") {
+      if (
+        parsed.status !== "active" &&
+        parsed.status !== "queued" &&
+        parsed.status !== "idle" &&
+        parsed.status !== "closed"
+      ) {
         return null;
       }
       if (typeof parsed.workspaceId !== "string") return null;