feat(FN-1401): integrate PluginRunner into runtime lifecycle

- Integrate PluginRunner into InProcessRuntime for plugin lifecycle management
- Wire plugin:created, plugin:updated, plugin:deleted events through runtime event bus
- Add plugin tools to StepSessionExecutor so plugins can provide tools during step execution
- Fix PluginRunner to pass PluginContext to task lifecycle hooks (onTaskCreated, onTaskUpdated, etc.)
- Add PluginRunner tests covering init/shutdown, timeout isolation, and sync event behavior
- Add InProcessRuntime tests verifying plugin integration
- Update memory documentation with plugin runner lifecycle wiring

packages/engine/src/runtimes/in-process-runtime.test.ts

@@ -38,9 +38,27 @@ vi.mock("@fusion/core", async () => {
         emit: vi.fn(),
       });
       self.on = vi.fn().mockReturnValue(self);
+      self.off = vi.fn();
       self.emit = vi.fn().mockReturnValue(true);
       return self;
     }),
+    PluginStore: vi.fn().mockImplementation(function() {
+      const self = {} as Record<string, unknown>;
+      self.init = vi.fn().mockResolvedValue(undefined);
+      self.getPlugin = vi.fn().mockResolvedValue({});
+      self.on = vi.fn();
+      self.off = vi.fn();
+      return self;
+    }),
+    PluginLoader: vi.fn().mockImplementation(function() {
+      const self = {} as Record<string, unknown>;
+      self.loadAllPlugins = vi.fn().mockResolvedValue({ loaded: 0, errors: 0 });
+      self.stopAllPlugins = vi.fn().mockResolvedValue(undefined);
+      self.getLoadedPlugins = vi.fn().mockReturnValue([]);
+      self.on = vi.fn();
+      self.off = vi.fn();
+      return self;
+    }),
   };
 });
 
@@ -79,6 +97,18 @@ vi.mock("../self-healing.js", async () => {
   };
 });
 
+// Mock the plugin runner
+vi.mock("../plugin-runner.js", async () => {
+  return {
+    PluginRunner: vi.fn().mockImplementation(() => ({
+      init: vi.fn().mockResolvedValue(undefined),
+      shutdown: vi.fn().mockResolvedValue(undefined),
+      getPluginTools: vi.fn().mockReturnValue([]),
+      getPluginRoutes: vi.fn().mockReturnValue([]),
+    })),
+  };
+});
+
 // Mock the executor
 vi.mock("../executor.js", async () => {
   return {

packages/engine/src/runtimes/in-process-runtime.ts

@@ -6,6 +6,8 @@ import type {
   AgentStore,
   HeartbeatInvocationSource,
   AgentHeartbeatRun,
+  PluginStore,
+  PluginLoader,
 } from "@fusion/core";
 import { Scheduler } from "../scheduler.js";
 import { TaskExecutor, type TaskExecutorOptions } from "../executor.js";
@@ -23,6 +25,7 @@ import { runtimeLog } from "../logger.js";
 import { StuckTaskDetector } from "../stuck-task-detector.js";
 import type { UsageLimitPauser } from "../usage-limit-detector.js";
 import { SelfHealingManager } from "../self-healing.js";
+import { PluginRunner } from "../plugin-runner.js";
 import { MissionAutopilot } from "../mission-autopilot.js";
 
 /**
@@ -76,6 +79,9 @@ export class InProcessRuntime
   /** Maps task IDs to agent IDs for lifecycle tracking */
   private taskAgentMap = new Map<string, string>();
   private lastActivityAt: string = new Date().toISOString();
+  private pluginRunner?: PluginRunner;
+  private pluginStore?: PluginStore;
+  private pluginLoader?: PluginLoader;
 
   /**
    * @param config - Runtime configuration
@@ -111,12 +117,30 @@ export class InProcessRuntime
 
     try {
       // 1. Initialize TaskStore
-      const { TaskStore } = await import("@fusion/core");
+      const { TaskStore, PluginStore: PluginStoreClass, PluginLoader: PluginLoaderClass } = await import("@fusion/core");
       this.taskStore = new TaskStore(this.config.workingDirectory);
       await this.taskStore.init();
       runtimeLog.log(`TaskStore initialized for project ${this.config.projectId}`);
 
-      // 2. Initialize WorktreePool
+      // 2. Initialize Plugin system (PluginStore + PluginLoader + PluginRunner)
+      this.pluginStore = new PluginStoreClass(this.taskStore.getFusionDir());
+      await this.pluginStore.init();
+
+      this.pluginLoader = new PluginLoaderClass({
+        pluginStore: this.pluginStore,
+        taskStore: this.taskStore,
+      });
+
+      this.pluginRunner = new PluginRunner({
+        pluginLoader: this.pluginLoader,
+        pluginStore: this.pluginStore,
+        taskStore: this.taskStore,
+        rootDir: this.config.workingDirectory,
+      });
+      await this.pluginRunner.init();
+      runtimeLog.log(`PluginRunner initialized`);
+
+      // 3. Initialize WorktreePool
       this.worktreePool = new WorktreePool();
 
       // Rehydrate pool from disk state (idle worktrees)
@@ -132,11 +156,11 @@ export class InProcessRuntime
         );
       }
 
-      // 3. Initialize global semaphore from CentralCore
+      // 4. Initialize global semaphore from CentralCore
       const globalLimit = await this.getGlobalConcurrencyLimit();
       this.globalSemaphore = new AgentSemaphore(() => globalLimit);
 
-      // 4. Initialize Scheduler
+      // 5. Initialize Scheduler
       const missionStore = this.taskStore.getMissionStore();
       const missionAutopilot = missionStore
         ? new MissionAutopilot(this.taskStore, missionStore)
@@ -180,6 +204,7 @@ export class InProcessRuntime
         pool: this.worktreePool,
         usageLimitPauser: this.usageLimitPauser,
         stuckTaskDetector: this.stuckTaskDetector,
+        pluginRunner: this.pluginRunner,
         missionStore,
         onSliceComplete: (slice) => {
           void this.scheduler.onSliceComplete(slice);
@@ -368,8 +393,9 @@ export class InProcessRuntime
    * 1. Set status to "stopping"
    * 2. Stop scheduler (no new tasks)
    * 3. Wait for executor to finish active tasks (with timeout)
-   * 4. Drain and cleanup worktree pool
-   * 5. Set status to "stopped"
+   * 4. Shutdown plugin runner
+   * 5. Drain and cleanup worktree pool
+   * 6. Set status to "stopped"
    *
    * @throws Error if shutdown timeout is exceeded
    */
@@ -435,7 +461,13 @@ export class InProcessRuntime
         );
       }
 
-      // 3. Drain and cleanup worktree pool
+      // 6. Shutdown plugin runner
+      if (this.pluginRunner) {
+        await this.pluginRunner.shutdown();
+        runtimeLog.log("PluginRunner shutdown complete");
+      }
+
+      // 7. Drain and cleanup worktree pool
       if (this.worktreePool) {
         const worktrees = this.worktreePool.drain();
         if (worktrees.length > 0) {