feat: add Pi subagent scheduler and child runtime

electron/coding-runtime/pi/event-projector.ts

@@ -7,6 +7,7 @@ import type {
   PublicUsage,
 } from '../contracts';
 import type { PiRpcEvent } from './rpc-client';
+import { subagentDetailsOfResult } from '../subagent-protocol';
 
 export interface PiEventProjectorOptions {
   createId(): string;
@@ -89,6 +90,49 @@ function outputBlocks(toolId: string, value: unknown): ConversationContentBlock[
   });
 }
 
+function projectToolResult(
+  snapshot: ConversationSnapshot,
+  tool: ConversationToolNode,
+  status: ConversationToolNode['status'],
+  value: unknown,
+): ConversationPatch[] {
+  const details = subagentDetailsOfResult(value);
+  const result = asRecord(value);
+  const unknownSubagentDetails = tool.toolName === 'subagent'
+    && result?.details !== undefined
+    && !details;
+  const output = unknownSubagentDetails
+    ? [{
+        kind: 'text' as const,
+        id: `${tool.id}:output:unavailable`,
+        text: 'Subagent details are unavailable for this version.',
+        status: 'complete' as const,
+      }]
+    : outputBlocks(tool.id, value);
+  const patches: ConversationPatch[] = [{
+    op: 'tool.upsert',
+    node: {
+      ...tool,
+      status,
+      output,
+      ...(details ? { details } : {}),
+    },
+  }];
+  const runId = snapshot.run.runId;
+  if (details && runId) {
+    patches.push({
+      op: 'subagent.upsert',
+      node: {
+        kind: 'subagent',
+        id: `subagent:${details.dispatchId}`,
+        runId,
+        details,
+      },
+    });
+  }
+  return patches;
+}
+
 function currentTool(snapshot: ConversationSnapshot, toolCallId: string): ConversationToolNode | undefined {
   return snapshot.nodes.find(
     (node): node is ConversationToolNode => node.kind === 'tool'
@@ -613,28 +657,19 @@ export class PiEventProjector {
       if (typeof event.toolCallId !== 'string') return [];
       const tool = currentTool(snapshot, event.toolCallId);
       if (!tool) return [];
-      return [{
-        op: 'tool.upsert',
-        node: {
-          ...tool,
-          status: 'running',
-          output: outputBlocks(tool.id, event.partialResult),
-        },
-      }];
+      return projectToolResult(snapshot, tool, 'running', event.partialResult);
     }
 
     if (event.type === 'tool_execution_end') {
       if (typeof event.toolCallId !== 'string') return [];
       const tool = currentTool(snapshot, event.toolCallId);
       if (!tool) return [];
-      return [{
-        op: 'tool.upsert',
-        node: {
-          ...tool,
-          status: event.isError === true ? 'error' : 'complete',
-          output: outputBlocks(tool.id, event.result),
-        },
-      }];
+      return projectToolResult(
+        snapshot,
+        tool,
+        event.isError === true ? 'error' : 'complete',
+        event.result,
+      );
     }
 
     if (event.type === 'message_end') {
@@ -642,14 +677,12 @@ export class PiEventProjector {
       if (message?.role === 'toolResult' && typeof message.toolCallId === 'string') {
         const tool = currentTool(snapshot, message.toolCallId);
         if (!tool) return [];
-        return [{
-          op: 'tool.upsert',
-          node: {
-            ...tool,
-            status: message.isError === true ? 'error' : 'complete',
-            output: outputBlocks(tool.id, message),
-          },
-        }];
+        return projectToolResult(
+          snapshot,
+          tool,
+          message.isError === true ? 'error' : 'complete',
+          message,
+        );
       }
       if (message?.role !== 'assistant') return [];
       const current = currentAssistant(snapshot);