feat(web): rewrite subagent conversations for FIFO activation

packages/client/runtime/src/client/sessions/manager.ts

@@ -153,7 +153,7 @@ export class SessionManager {
   selectSubagent(address: SubagentAddress): void {
     const catalog = this.catalogs.get(address.parentSessionId)
     const entry = catalog?.entries.find(candidate => candidate.id === address.childSessionId)
-    if (entry === undefined || entry.kind !== 'child') {
+    if (entry === undefined || entry.kind !== 'child' || entry.mode !== address.mode) {
       throw new Error(`sessions.selectSubagent: ${address.childSessionId} is not a healthy catalog child`)
     }
     this.addresses.set(address.childSessionId, address)
@@ -625,7 +625,7 @@ export class SessionManager {
       case 'host/session-removed': {
         this.recordMutation({ kind: 'remove', sessionId: frame.sessionId })
         if (this.addresses.has(frame.sessionId)) {
-          // A continuable activation detaching is not durable child deletion:
+          // An Activation detaching is not durable child deletion:
           // keep the addressed conversation usable and return its catalog row
           // to the inactive state.
           this.sessions.get(frame.sessionId)?.handleRunning(false)

packages/client/runtime/src/client/sessions/service.ts

@@ -642,7 +642,7 @@ export class SessionsService implements ISessions {
       if (child?.kind === 'child') {
         byId[current] = {
           id: current,
-          displayTitle: child.label,
+          displayTitle: child.label ?? current,
           parentId: currentAddress.parentSessionId,
           origin: 'subagent',
           running: child.activity === 'running',
@@ -660,7 +660,8 @@ export class SessionsService implements ISessions {
     } else if (byId[current] !== undefined
       && (persisted !== current
         || this.selection.getSnapshot().subagentAddress?.childSessionId !== currentAddress?.childSessionId
-        || this.selection.getSnapshot().subagentAddress?.parentSessionId !== currentAddress?.parentSessionId)) {
+        || this.selection.getSnapshot().subagentAddress?.parentSessionId !== currentAddress?.parentSessionId
+        || this.selection.getSnapshot().subagentAddress?.mode !== currentAddress?.mode)) {
       this.selection.set({
         sessionId: current,
         ...(currentAddress === undefined ? {} : { subagentAddress: currentAddress }),

packages/client/runtime/src/client/sessions/session.ts

@@ -223,6 +223,15 @@ export class Session implements SessionFace {
     try {
       if (this.address === undefined) {
         result = (await this.api.sessions.prompt({ sessionId: this.sessionId, mode, content })).result
+      } else if (this.address.mode === 'one-shot') {
+        result = {
+          ok: false,
+          error: {
+            code: 'subagent-not-resumable',
+            message: 'one-shot subagent conversations are read-only',
+            details: { childSessionId: this.address.childSessionId },
+          },
+        }
       } else {
         const routed = (await this.api.subagents.prompt({ ...this.address, content })).result
         result = routed.ok ? { ok: true, value: { accepted: true } } : routed
@@ -270,7 +279,7 @@ export class Session implements SessionFace {
       const result: RpcResult<{ accepted: true }> = {
         ok: false,
         error: {
-          code: 'subagent-not-delivered',
+          code: 'subagent-delivery-unavailable',
           message: 'subagent activation cancellation is unavailable',
           details: { childSessionId: this.address.childSessionId },
         },
@@ -512,6 +521,7 @@ export class Session implements SessionFace {
   configureSubagent(address: SubagentAddress | undefined, parentAvailable = false): void {
     const same = this.address?.parentSessionId === address?.parentSessionId
       && this.address?.childSessionId === address?.childSessionId
+      && this.address?.mode === address?.mode
     this.address = address
     this.parentAvailable = parentAvailable
     if (!same && this.openState !== 'cold') void this.resync()