test: add clipboard and notification rules tests

Adds 55 tests for clipboard store pure functions (detectLanguage for 12
languages + formatTimestamp with fake timers) and 13 tests for the
notification rules state machine (reconnect transition logic and no-op
handlers). Total test count now 698 across 30 files.

src/lib/notifications/rules.test.ts

@@ -0,0 +1,150 @@
+/**
+ * Notification Rules Tests
+ *
+ * Tests the connection status change handler, which fires a connection
+ * notification sound exactly once per reconnect cycle.
+ *
+ * What this module does:
+ * - Tracks the previous connection status in module-level state
+ * - Fires a notification only when transitioning from a non-connected
+ *   state (disconnected/connecting) to "connected"
+ * - Ignores the initial connection (null → connected) to avoid noisy
+ *   notifications on app start
+ * - Provides no-op handlers for tool execution and user messages
+ *   (reserved for future notification rules)
+ * - cleanupNotificationRules() resets tracking state on teardown
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+const { mockNotifyConnection } = vi.hoisted(() => ({
+  mockNotifyConnection: vi.fn(),
+}));
+
+vi.mock("./notificationManager", () => ({
+  notificationManager: {
+    notifyConnection: mockNotifyConnection,
+  },
+}));
+
+import {
+  handleConnectionStatusChange,
+  handleToolExecution,
+  handleNewUserMessage,
+  initializeNotificationRules,
+  cleanupNotificationRules,
+} from "./rules";
+
+// ---
+
+describe("handleConnectionStatusChange", () => {
+  beforeEach(() => {
+    mockNotifyConnection.mockReset();
+    cleanupNotificationRules(); // Reset module-level previousConnectionStatus to null
+  });
+
+  describe("initial connection (null → status)", () => {
+    it("does not notify on first connection (null → connected)", () => {
+      // previousConnectionStatus is null (falsy), so condition is not met
+      handleConnectionStatusChange("connected");
+      expect(mockNotifyConnection).not.toHaveBeenCalled();
+    });
+
+    it("does not notify when disconnecting from initial state (null → disconnected)", () => {
+      handleConnectionStatusChange("disconnected");
+      expect(mockNotifyConnection).not.toHaveBeenCalled();
+    });
+
+    it("does not notify when entering connecting from initial state (null → connecting)", () => {
+      handleConnectionStatusChange("connecting");
+      expect(mockNotifyConnection).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("reconnection (disconnected → connected)", () => {
+    it("notifies when reconnecting after a disconnection", () => {
+      handleConnectionStatusChange("disconnected");
+      handleConnectionStatusChange("connected");
+      expect(mockNotifyConnection).toHaveBeenCalledWith();
+    });
+
+    it("notifies exactly once per reconnect", () => {
+      handleConnectionStatusChange("disconnected");
+      handleConnectionStatusChange("connected");
+      expect(mockNotifyConnection).toHaveBeenCalledTimes(1);
+    });
+  });
+
+  describe("reconnection (connecting → connected)", () => {
+    it("notifies when transitioning from connecting to connected", () => {
+      handleConnectionStatusChange("connecting");
+      handleConnectionStatusChange("connected");
+      expect(mockNotifyConnection).toHaveBeenCalledWith();
+    });
+  });
+
+  describe("already connected (connected → connected)", () => {
+    it("does not notify when already connected", () => {
+      handleConnectionStatusChange("disconnected");
+      handleConnectionStatusChange("connected"); // First connection — notifies
+      mockNotifyConnection.mockReset();
+
+      handleConnectionStatusChange("connected"); // Second — same status, no notify
+      expect(mockNotifyConnection).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("disconnecting (connected → disconnected)", () => {
+    it("does not notify when disconnecting", () => {
+      handleConnectionStatusChange("disconnected");
+      handleConnectionStatusChange("connected");
+      mockNotifyConnection.mockReset();
+
+      handleConnectionStatusChange("disconnected");
+      expect(mockNotifyConnection).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("multiple reconnect cycles", () => {
+    it("notifies once per reconnect cycle", () => {
+      // First cycle
+      handleConnectionStatusChange("disconnected");
+      handleConnectionStatusChange("connected");
+      expect(mockNotifyConnection).toHaveBeenCalledTimes(1);
+
+      mockNotifyConnection.mockReset();
+
+      // Second cycle
+      handleConnectionStatusChange("disconnected");
+      handleConnectionStatusChange("connected");
+      expect(mockNotifyConnection).toHaveBeenCalledTimes(1);
+    });
+  });
+});
+
+describe("cleanupNotificationRules", () => {
+  it("resets state so the next connection is treated as the first", () => {
+    // Establish a known previous status
+    handleConnectionStatusChange("disconnected");
+    // Now cleanup
+    cleanupNotificationRules();
+    // After cleanup, previousConnectionStatus is null again
+    // So the next "connected" should NOT notify (treated as initial connection)
+    handleConnectionStatusChange("connected");
+    expect(mockNotifyConnection).not.toHaveBeenCalled();
+  });
+});
+
+describe("no-op handlers", () => {
+  it("handleToolExecution does not throw", () => {
+    expect(() => handleToolExecution("Bash")).not.toThrow();
+  });
+
+  it("handleNewUserMessage does not throw", () => {
+    expect(() => handleNewUserMessage()).not.toThrow();
+  });
+
+  it("initializeNotificationRules does not throw", () => {
+    expect(() => initializeNotificationRules()).not.toThrow();
+  });
+});