Fix email delivery and body battery null handling

- Add PocketBase admin auth to notifications endpoint (was returning 0 users)
- Store null instead of 100 for body battery when Garmin returns no data
- Update decision engine to skip body battery rules when values are null
- Dashboard and email already display "N/A" for null values

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/api/cron/notifications/route.test.ts

@@ -9,7 +9,8 @@ let mockUsers: User[] = [];
 let mockDailyLogs: DailyLog[] = [];
 const mockPbUpdate = vi.fn().mockResolvedValue({ id: "log123" });
 
-// Mock PocketBase
+// Mock PocketBase with admin auth
+const mockAuthWithPassword = vi.fn().mockResolvedValue({ id: "admin" });
 vi.mock("@/lib/pocketbase", () => ({
   createPocketBaseClient: vi.fn(() => ({
     collection: vi.fn((name: string) => ({
@@ -23,10 +24,21 @@ vi.mock("@/lib/pocketbase", () => ({
         return [];
       }),
       update: mockPbUpdate,
+      authWithPassword: (email: string, password: string) =>
+        mockAuthWithPassword(email, password),
     })),
   })),
 }));
 
+// Mock logger
+vi.mock("@/lib/logger", () => ({
+  logger: {
+    info: vi.fn(),
+    warn: vi.fn(),
+    error: vi.fn(),
+  },
+}));
+
 // Mock email sending
 const mockSendDailyEmail = vi.fn().mockResolvedValue(undefined);
 const mockSendTokenExpirationWarning = vi.fn().mockResolvedValue(undefined);
@@ -110,6 +122,9 @@ describe("POST /api/cron/notifications", () => {
     mockUsers = [];
     mockDailyLogs = [];
     process.env.CRON_SECRET = validSecret;
+    process.env.POCKETBASE_ADMIN_EMAIL = "admin@example.com";
+    process.env.POCKETBASE_ADMIN_PASSWORD = "admin-password";
+    mockAuthWithPassword.mockResolvedValue({ id: "admin" });
     // Mock current time to 07:00 UTC
     vi.useFakeTimers();
     vi.setSystemTime(new Date("2025-01-15T07:00:00Z"));
@@ -143,6 +158,36 @@ describe("POST /api/cron/notifications", () => {
 
       expect(response.status).toBe(401);
     });
+
+    it("returns 500 when POCKETBASE_ADMIN_EMAIL is not set", async () => {
+      process.env.POCKETBASE_ADMIN_EMAIL = "";
+
+      const response = await POST(createMockRequest(`Bearer ${validSecret}`));
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.error).toBe("Server misconfiguration");
+    });
+
+    it("returns 500 when POCKETBASE_ADMIN_PASSWORD is not set", async () => {
+      process.env.POCKETBASE_ADMIN_PASSWORD = "";
+
+      const response = await POST(createMockRequest(`Bearer ${validSecret}`));
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.error).toBe("Server misconfiguration");
+    });
+
+    it("returns 500 when PocketBase admin auth fails", async () => {
+      mockAuthWithPassword.mockRejectedValueOnce(new Error("Auth failed"));
+
+      const response = await POST(createMockRequest(`Bearer ${validSecret}`));
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.error).toBe("Database authentication failed");
+    });
   });
 
   describe("User time matching", () => {