feat(quick-pane): add constrained agent window

src/bridge/agent-registry.js

@@ -309,7 +309,9 @@ export function createAgentRegistry({
 			version: 2,
 			migrated: true,
 			directories: [...managedWorktrees].sort(),
-			runtimes: [...runtimesByRuntimeId.values()].map((runtime) => ({
+			runtimes: [...runtimesByRuntimeId.values()]
+				.filter((runtime) => !runtime.ephemeral)
+				.map((runtime) => ({
 				runtimeId: runtime.runtimeId,
 				worktreePath: runtime.worktreePath,
 				...(runtime.sessionPath ? { sessionPath: runtime.sessionPath } : {}),
@@ -326,7 +328,7 @@ export function createAgentRegistry({
 	}
 
 	function addWorktreeRuntime(runtime) {
-		managedWorktrees.add(runtime.worktreePath);
+		if (!runtime.ephemeral) managedWorktrees.add(runtime.worktreePath);
 		let runtimes = runtimesByWorktreePath.get(runtime.worktreePath);
 		if (!runtimes) {
 			runtimes = new Set();
@@ -573,6 +575,7 @@ export function createAgentRegistry({
 		sessionPath,
 		sessionId,
 		legacyDefault = false,
+		ephemeral = false,
 		openedAt = new Date().toISOString(),
 	}) {
 		return {
@@ -583,6 +586,7 @@ export function createAgentRegistry({
 			sessionPath,
 			sessionId,
 			legacyDefault,
+			ephemeral,
 			openedAt,
 			state: "starting",
 			stateVersion: 0,
@@ -719,13 +723,16 @@ export function createAgentRegistry({
 			sessionPath,
 			sessionId,
 			legacyDefault = false,
+			ephemeral = false,
 			openedAt,
 		},
 		{ restore = false } = {},
 	) {
 		if (stopping) throw new Error("agent registry is stopping");
 		const canonicalPath = await realpath(worktreePath);
-		const sessionDir = sessionDirectoryFor(sessionRoot, canonicalPath);
+		const sessionDir = ephemeral
+			? path.join(sessionRoot, "quick", runtimeId)
+			: sessionDirectoryFor(sessionRoot, canonicalPath);
 		await mkdir(sessionDir, { recursive: true, mode: SESSION_DIRECTORY_MODE });
 		await chmod(sessionDir, SESSION_DIRECTORY_MODE);
 		let ownedPath;
@@ -757,6 +764,7 @@ export function createAgentRegistry({
 				sessionPath: ownedPath,
 				sessionId,
 				legacyDefault,
+				ephemeral,
 				openedAt,
 			});
 			if (stopping) throw new Error("agent registry is stopping");
@@ -778,7 +786,7 @@ export function createAgentRegistry({
 			});
 			try {
 				await launch(runtime);
-				await persistWorkspace();
+				if (!runtime.ephemeral) await persistWorkspace();
 				publishWorkspace("runtime_opened", runtime, {
 					runtime: publicRuntime(runtime),
 				});
@@ -974,7 +982,7 @@ export function createAgentRegistry({
 		// Remove desired-open/UI intent now, but retain the session lease until
 		// the old child can no longer write to its JSONL file.
 		unindexRuntime(runtime, { releaseSessionLease: false });
-		await persistWorkspace();
+		if (!runtime.ephemeral) await persistWorkspace();
 		runtime.stopped = true;
 		runtime.supervisor?.stop();
 		let stopConfirmed = true;
@@ -1002,6 +1010,8 @@ export function createAgentRegistry({
 			}
 		}
 		if (stopConfirmed) releaseClosedSessionLease(runtime);
+		if (runtime.ephemeral && stopConfirmed)
+			await rm(runtime.sessionDir, { recursive: true, force: true }).catch(() => {});
 		runtime.state = "stopped";
 		publishWorkspace("runtime_closed", runtime, {
 			runtimeId: runtime.runtimeId,
@@ -1206,10 +1216,18 @@ export function createAgentRegistry({
 		async createSessionRuntime(worktreePath) {
 			return openRuntime({ worktreePath });
 		},
+		async createQuickRuntime(worktreePath) {
+			return openRuntime({ worktreePath, ephemeral: true });
+		},
 		async openSessionRuntime(worktreePath, sessionPath) {
 			return openRuntime({ worktreePath, sessionPath });
 		},
 		closeSessionRuntime: closeRuntime,
+		async closeQuickRuntime(runtimeId) {
+			const runtime = getRuntime(runtimeId);
+			if (!runtime.ephemeral) throw new Error("runtime is not a quick runtime");
+			return closeRuntime(runtimeId);
+		},
 		listAgents() {
 			return [...runtimesByAgentId.values()]
 				.map(publicAgent)

src/bridge/service.js

@@ -46,6 +46,12 @@ export async function startBridgeService({
 							request.payload.worktreePath,
 						),
 					};
+				case "create_quick_runtime":
+					return {
+						runtime: await registry.createQuickRuntime(
+							request.payload.worktreePath,
+						),
+					};
 				case "open_session_runtime":
 					return {
 						runtime: await registry.openSessionRuntime(
@@ -55,6 +61,8 @@ export async function startBridgeService({
 					};
 				case "close_session_runtime":
 					return registry.closeSessionRuntime(request.payload.runtimeId);
+				case "close_quick_runtime":
+					return registry.closeQuickRuntime(request.payload.runtimeId);
 				case "list_directory_sessions":
 					return {
 						sessions: await registry.listDirectorySessions(