feat: Add errand tRPC router with all 9 procedures and comprehensive tests

Implements the errand workflow for small isolated changes that spawn a
dedicated agent in a git worktree:
- errand.create: branch + worktree + DB record + agent spawn
- errand.list / errand.get / errand.diff: read procedures
- errand.complete: transitions active→pending_review, stops agent
- errand.merge: merges branch, handles conflicts with conflictFiles
- errand.delete / errand.abandon: cleanup worktree, branch, agent
- errand.sendMessage: delivers user message directly to running agent

Supporting changes:
- Add 'errand' to AgentMode union and agents.mode enum
- Add sendUserMessage() to AgentManager interface and MockAgentManager
- MockAgentManager now accepts optional agentRepository to persist agents
  to the DB (required for FK constraint satisfaction in tests)
- Add ORDER BY createdAt DESC, id DESC to errand findAll
- Fix dispatch/manager.test.ts missing sendUserMessage mock

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/server/agent/mock-manager.ts

@@ -26,6 +26,7 @@ import type {
   AgentDeletedEvent,
   AgentWaitingEvent,
 } from '../events/index.js';
+import type { AgentRepository } from '../db/repositories/agent-repository.js';
 
 /**
  * Scenario configuration for mock agent behavior.
@@ -83,10 +84,12 @@ export class MockAgentManager implements AgentManager {
   private scenarioOverrides: Map<string, MockAgentScenario> = new Map();
   private defaultScenario: MockAgentScenario;
   private eventBus?: EventBus;
+  private agentRepository?: AgentRepository;
 
-  constructor(options?: { eventBus?: EventBus; defaultScenario?: MockAgentScenario }) {
+  constructor(options?: { eventBus?: EventBus; defaultScenario?: MockAgentScenario; agentRepository?: AgentRepository }) {
     this.eventBus = options?.eventBus;
     this.defaultScenario = options?.defaultScenario ?? DEFAULT_SCENARIO;
+    this.agentRepository = options?.agentRepository;
   }
 
   /**
@@ -111,7 +114,7 @@ export class MockAgentManager implements AgentManager {
    * Completion happens async via setTimeout (even if delay=0).
    */
   async spawn(options: SpawnAgentOptions): Promise<AgentInfo> {
-    const { taskId, prompt } = options;
+    const { taskId } = options;
     const name = options.name ?? `agent-${taskId?.slice(0, 6) ?? 'noTask'}`;
 
     // Check name uniqueness
@@ -121,11 +124,29 @@ export class MockAgentManager implements AgentManager {
       }
     }
 
-    const agentId = randomUUID();
     const sessionId = randomUUID();
     const worktreeId = randomUUID();
     const now = new Date();
 
+    // Persist to agentRepository when provided (required for FK constraints in tests)
+    let agentId: string;
+    if (this.agentRepository) {
+      const dbAgent = await this.agentRepository.create({
+        name,
+        worktreeId,
+        taskId: taskId ?? null,
+        initiativeId: options.initiativeId ?? null,
+        sessionId,
+        status: 'running',
+        mode: options.mode ?? 'execute',
+        provider: options.provider ?? 'claude',
+        accountId: null,
+      });
+      agentId = dbAgent.id;
+    } else {
+      agentId = randomUUID();
+    }
+
     // Determine scenario (override takes precedence — use original name or generated)
     const scenario = this.scenarioOverrides.get(name) ?? this.defaultScenario;
 
@@ -507,6 +528,18 @@ export class MockAgentManager implements AgentManager {
     return true;
   }
 
+  /**
+   * Deliver a user message to a running errand agent.
+   * Mock implementation: no-op (simulates message delivery without actual process interaction).
+   */
+  async sendUserMessage(agentId: string, _message: string): Promise<void> {
+    const record = this.agents.get(agentId);
+    if (!record) {
+      throw new Error(`Agent '${agentId}' not found`);
+    }
+    // Mock: succeed silently — message delivery is a no-op in tests
+  }
+
   /**
    * Clear all agents and pending timers.
    * Useful for test cleanup.

apps/server/agent/types.ts

@@ -15,7 +15,7 @@ export type AgentStatus = 'idle' | 'running' | 'waiting_for_input' | 'stopped' |
  * - plan: Plan initiative into phases
  * - detail: Detail phase into individual tasks
  */
-export type AgentMode = 'execute' | 'discuss' | 'plan' | 'detail' | 'refine' | 'chat';
+export type AgentMode = 'execute' | 'discuss' | 'plan' | 'detail' | 'refine' | 'chat' | 'errand';
 
 /**
  * Context data written as input files in agent workdir before spawn.
@@ -257,4 +257,14 @@ export interface AgentManager {
     question: string,
     fromAgentId: string,
   ): Promise<boolean>;
+
+  /**
+   * Deliver a user message to a running errand agent.
+   * Does not use the conversations table — the message is injected directly
+   * into the agent's Claude Code session as a resume prompt.
+   *
+   * @param agentId - The errand agent to message
+   * @param message - The user's message text
+   */
+  sendUserMessage(agentId: string, message: string): Promise<void>;
 }