feat: message queue/interrupt system, CORS fix, mobile fixes, chat splitting

- Add message queue allowing users to send messages while agent is running
- Queue messages are injected into tool results as [USER INTERRUPT]
- Retrieve tool interrupted via Promise.race when user message arrives
- Queued messages show with 'queued' badge and cancel button
- Consumed messages repositioned and chat splits at interrupt point
- New assistant message block created after interrupt for clean flow
- Add POST /chat/cancel endpoint for cancelling queued messages
- Fix CORS to allow any origin (Tailscale/LAN access)
- Fix crypto.randomUUID fallback for non-secure contexts (HTTP)
- Fix frontend API URL derivation from page hostname
- Auto-create DB tab if missing on processMessage (foreign key fix)
- Add error logging to processMessage catch block
- Fix working directory input sync on agent switch
- Fix agent mode button to re-apply agent settings

1 files changed, 25 insertions, 3 deletions

diff --git a/packages/core/src/tools/retrieve.ts b/packages/core/src/tools/retrieve.ts
index 93f4c89..8e14a96 100644
--- a/packages/core/src/tools/retrieve.ts
+++ b/packages/core/src/tools/retrieve.ts
@@ -1,5 +1,5 @@
 import { z } from "zod";
-import type { ToolDefinition } from "../types/index.js";
+import type { ToolDefinition, ToolExecuteContext } from "../types/index.js";
 
 export interface RetrieveCallbacks {
 	getResult(
@@ -24,11 +24,33 @@ export function createRetrieveTool(callbacks: RetrieveCallbacks): ToolDefinition
 		parameters: z.object({
 			agent_id: z.string().describe("The agent_id returned by a previous summon call."),
 		}),
-		execute: async (args: Record<string, unknown>): Promise<string> => {
+		execute: async (args: Record<string, unknown>, context?: ToolExecuteContext): Promise<string> => {
 			const agentId = args.agent_id as string;
+			const queueCallbacks = context?.queueCallbacks;
 
 			try {
-				const outcome = await callbacks.getResult(agentId);
+				let outcome: { status: "done"; result: string } | { status: "error"; error: string };
+
+			if (queueCallbacks) {
+				const childPromise = callbacks.getResult(agentId);
+				const { promise: queuePromise, cancel: cancelQueueWait } = queueCallbacks.waitForQueuedMessage();
+				const queueSignal = queuePromise.then(() => "QUEUE_INTERRUPT" as const);
+
+				const raceResult = await Promise.race([childPromise, queueSignal]);
+
+				if (raceResult === "QUEUE_INTERRUPT") {
+					const queuedMsgs = queueCallbacks.dequeueMessages();
+					const userMessages = queuedMsgs.map((m) => m.message).join("\n---\n");
+					return `The subagent (agent_id: ${agentId}) has not completed its task yet. You will need to call retrieve with this agent_id again later to get the result.\n\n[USER INTERRUPT]\nThe user has sent you message(s) while you were working. You MUST address these before continuing with your current task:\n\n${userMessages}`;
+				}
+
+				// Child finished first — clean up the queue listener
+				cancelQueueWait();
+				outcome = raceResult;
+				} else {
+					outcome = await callbacks.getResult(agentId);
+				}
+
 				if (outcome.status === "done") {
 					return ["<agent_result>", outcome.result, "</agent_result>"].join("\n");
 				}