feat(FN-1053): add AI prompt executor for cron workflow steps

- Define AiPromptExecutor type and update CronRunner constructor to accept injected executor
- Implement executeAiPromptStep with real agent session execution in worktrees
- Create createAiPromptStepExecutor factory and wire up in dashboard CLI
- Add comprehensive tests for AI prompt step execution (mock agent, errors, output capture)
- Fix mock typing for dashboard test build compatibility

packages/cli/src/commands/__tests__/dashboard.test.ts

@@ -122,6 +122,7 @@ vi.mock("@fusion/engine", async (importOriginal) => {
     })),
     scanIdleWorktrees: vi.fn().mockResolvedValue([]),
     cleanupOrphanedWorktrees: vi.fn().mockResolvedValue(0),
+    createAiPromptExecutor: vi.fn().mockResolvedValue(vi.fn().mockResolvedValue("mock AI response")),
   };
 });
 

packages/cli/src/commands/dashboard.ts

@@ -4,7 +4,7 @@ import { createInterface } from "node:readline";
 import { TaskStore, AutomationStore, CentralCore, AgentStore, getTaskMergeBlocker } from "@fusion/core";
 import type { Settings, TaskDetail, PrInfo } from "@fusion/core";
 import { createServer, GitHubClient } from "@fusion/dashboard";
-import { TriageProcessor, TaskExecutor, Scheduler, AgentSemaphore, WorktreePool, aiMergeTask, UsageLimitPauser, PRIORITY_MERGE, scanIdleWorktrees, cleanupOrphanedWorktrees, NtfyNotifier, PrMonitor, PrCommentHandler, CronRunner, StuckTaskDetector, SelfHealingManager, MissionAutopilot } from "@fusion/engine";
+import { TriageProcessor, TaskExecutor, Scheduler, AgentSemaphore, WorktreePool, aiMergeTask, UsageLimitPauser, PRIORITY_MERGE, scanIdleWorktrees, cleanupOrphanedWorktrees, NtfyNotifier, PrMonitor, PrCommentHandler, CronRunner, StuckTaskDetector, SelfHealingManager, MissionAutopilot, createAiPromptExecutor } from "@fusion/engine";
 import { AuthStorage, DefaultPackageManager, ModelRegistry, SettingsManager, discoverAndLoadExtensions, getAgentDir, createExtensionRuntime } from "@mariozechner/pi-coding-agent";
 
 /**
@@ -653,7 +653,8 @@ export async function runDashboard(port: number, opts: { paused?: boolean; dev?:
     missionAutopilot.setScheduler(scheduler);
 
     // ── CronRunner: scheduled task execution ──────────────────────────
-    const cronRunner = new CronRunner(store, automationStore);
+    const aiPromptExecutor = await createAiPromptExecutor(cwd);
+    const cronRunner = new CronRunner(store, automationStore, { aiPromptExecutor });
     cronRunner.start();
 
     triage.start();