fix(test): mock canonicalStateStore in session tests

Session tests mocked fs/promises but not the canonical-store module.
The canonicalStateStore singleton inherited the mocked fs, causing
pathExists to return true while readFile returned undefined — crashing
JSON.parse. Mock the entire canonical-store module with stubs for
upsertSession, appendEvent, and endSession.

Author: StackMemory Bot (CLI)

src/core/session/__tests__/session-manager.test.ts

@@ -21,6 +21,15 @@ vi.mock('child_process', () => ({
   execSync: vi.fn().mockReturnValue('main\n'),
 }));
 
+vi.mock('../../shared-state/canonical-store.js', () => ({
+  canonicalStateStore: {
+    upsertSession: vi.fn().mockResolvedValue({}),
+    appendEvent: vi.fn().mockResolvedValue(undefined),
+    endSession: vi.fn().mockResolvedValue(undefined),
+    initialize: vi.fn().mockResolvedValue(undefined),
+  },
+}));
+
 describe('SessionManager', () => {
   let manager: SessionManager;
 

src/core/session/__tests__/session.test.ts

@@ -26,6 +26,15 @@ vi.mock('fs/promises', () => ({
   access: vi.fn(),
 }));
 
+vi.mock('../../shared-state/canonical-store.js', () => ({
+  canonicalStateStore: {
+    upsertSession: vi.fn().mockResolvedValue({}),
+    appendEvent: vi.fn().mockResolvedValue(undefined),
+    endSession: vi.fn().mockResolvedValue(undefined),
+    initialize: vi.fn().mockResolvedValue(undefined),
+  },
+}));
+
 vi.mock('child_process', () => ({
   execSync: vi.fn().mockReturnValue('main\n'),
 }));