fix(queue): consume queued messages after a turn ends (start a new turn)

A message queued while the agent was mid-turn was only handled if it
arrived DURING a tool batch (injected as a [USER INTERRUPT]). If it
landed after the last tool call — or the turn had no tools — the agent
silently appended it to history and ended the turn with no response, so
it sat there unanswered. This affected both user-queued messages and
agent-queued ones (send_to_tab).

- agent.ts: stop the end-of-turn drain that swallowed trailing queued
  messages into history. They now stay on the queue.
- agent-manager: after a CLEAN turn settles, continueFromQueue() drains
  the queue and starts a fresh turn to answer it. Skipped on a
  user-stopped or errored turn (queue preserved for the next send).
- Loop safety: continuation draws from the existing autoWakeBudget, so a
  runaway agent<->agent chain is bounded; human sends refill it, so human
  conversations are never throttled.
- dequeueMessages now tags message-consumed with reason
  "interrupt" | "continuation"; the frontend collapses continuation-
  consumed queued bubbles into the next turn's initiator row (avoids the
  linger/dup traps documented in queue-interrupt-reconcile-edge-cases.md).
- Tests: agent (no-swallow + interrupt regression), agent-manager
  (continuation, no-op when empty, user-stop preserves queue, bounded
  loop), frontend (continuation bubble becomes next initiator).
- wishlist: remove the now-fixed item.

2 files changed, 15 insertions, 1 deletions

diff --git a/packages/core/src/agent/agent.ts b/packages/core/src/agent/agent.ts
index c2dfef1..c6f1322 100644
--- a/packages/core/src/agent/agent.ts
+++ b/packages/core/src/agent/agent.ts
diff --git a/packages/core/src/types/index.ts b/packages/core/src/types/index.ts
index a4230ca..ced3dc2 100644
--- a/packages/core/src/types/index.ts
+++ b/packages/core/src/types/index.ts
@@ -275,7 +275,21 @@ export type AgentEvent =
 			agentModels?: Array<{ key_id: string; model_id: string }> | null;
 	  }
 	| { type: "message-queued"; tabId: string; messageId: string; message: string }
-	| { type: "message-consumed"; tabId: string; messageIds: string[] }
+	| {
+			type: "message-consumed";
+			tabId: string;
+			messageIds: string[];
+			/**
+			 * Why the queue was drained:
+			 *  - "interrupt": consumed mid-turn, folded into a running turn's tool
+			 *    result as a [USER INTERRUPT]. The optimistic bubble collapses into
+			 *    that sealed turn.
+			 *  - "continuation": consumed between turns to START a new turn. The
+			 *    optimistic bubble becomes that new turn's initiating user row.
+			 * Absent ⇒ treat as "interrupt" (back-compat).
+			 */
+			reason?: "interrupt" | "continuation";
+	  }
 	| { type: "message-cancelled"; tabId: string; messageId: string };
 
 // ─── Tool Types ──────────────────────────────────────────────────