feat(coding): add core host api composition

electron/coding-runtime/pi/runtime.ts

@@ -12,7 +12,11 @@ import {
 import { PiProviderRefreshCoordinator } from './provider-refresh';
 import type {
   CodingConversationRuntime,
+  CodingRuntimeCommand,
+  CodingRuntimeDiagnostics,
   CodingRuntimePublicError,
+  ConversationInteraction,
+  ConversationInteractionResponse,
   ConversationModelState,
   ConversationPatch,
   ConversationPatchEnvelope,
@@ -78,7 +82,6 @@ import { PiManagedExtensionHost } from './extension-host';
 import type { PiSubagentScheduler } from './subagent';
 import {
   PiInteractionStore,
-  type PiInteractionResponse,
 } from './interaction';
 import {
   PiExtensionUiProjector,
@@ -836,6 +839,52 @@ export class PiConversationRuntime implements CodingConversationRuntime {
     this.hydrationFlights.delete(conversationId);
   }
 
+  async listCommands(conversationId: string): Promise<CodingRuntimeCommand[]> {
+    const state = this.pool.getState(conversationId);
+    if (!state || state.state === 'spawning' || state.state === 'crashed') return [];
+    const response = await this.pool.request<unknown>(
+      conversationId,
+      { type: 'get_commands' },
+      { retry: 'read-only-once' },
+    );
+    const record = response.data && typeof response.data === 'object' && !Array.isArray(response.data)
+      ? response.data as Record<string, unknown>
+      : null;
+    const candidates = Array.isArray(response.data)
+      ? response.data
+      : Array.isArray(record?.commands)
+        ? record.commands
+        : [];
+    return candidates.flatMap((candidate) => {
+      if (!candidate || typeof candidate !== 'object' || Array.isArray(candidate)) return [];
+      const command = candidate as Record<string, unknown>;
+      const name = typeof command.name === 'string' ? command.name.trim() : '';
+      if (!name) return [];
+      return [{
+        name,
+        ...(typeof command.description === 'string'
+          ? { description: command.description }
+          : {}),
+      }];
+    });
+  }
+
+  async listInteractions(conversationId?: string): Promise<ConversationInteraction[]> {
+    return this.interactions.list(conversationId);
+  }
+
+  getDiagnostics(): CodingRuntimeDiagnostics {
+    return this.pool.getDiagnostics();
+  }
+
+  markProviderStale(): void {
+    this.pool.markProviderStale();
+  }
+
+  markResourcesStale(): void {
+    this.pool.markResourcesStale();
+  }
+
   subscribe(listener: (patch: ConversationPatchEnvelope) => void): () => void {
     this.listeners.add(listener);
     return () => this.listeners.delete(listener);
@@ -843,7 +892,7 @@ export class PiConversationRuntime implements CodingConversationRuntime {
 
   async respondInteraction(
     conversationId: string,
-    response: PiInteractionResponse,
+    response: ConversationInteractionResponse,
   ): Promise<void> {
     await this.interactions.respond(conversationId, response);
   }