Remove dead token-based verification system

- Remove verificationsCache array and loadVerifications() function from verification.ts
- Remove verifyToken() and verifyTokenSync() functions (multi-replica unsafe, never used)
- Remove createVerification() function (stores unused data)
- Remove GET /verify route and verifyPage() helper function
- Remove loadVerifications() call from startup
- Remove createVerification() usage from signup route
- Update imports and test mocks to match removed functions
- Keep active 6-digit code system intact (createPendingVerification, verifyCode, etc.)

All 559 tests passing. The active verification system using pending_verifications
table and 6-digit codes continues to work normally.

src/__tests__/signup.test.ts

@@ -8,7 +8,7 @@ beforeEach(async () => {
   vi.clearAllMocks();
   vi.resetModules();
 
-  const { isEmailVerified, createPendingVerification, verifyCode, createVerification } = await import("../services/verification.js");
+  const { isEmailVerified, createPendingVerification, verifyCode } = await import("../services/verification.js");
   const { sendVerificationEmail } = await import("../services/email.js");
   const { createFreeKey } = await import("../services/keys.js");
 
@@ -16,7 +16,7 @@ beforeEach(async () => {
   vi.mocked(createPendingVerification).mockResolvedValue({ email: "test@test.com", code: "123456", createdAt: "", expiresAt: "", attempts: 0 });
   vi.mocked(verifyCode).mockResolvedValue({ status: "ok" });
   vi.mocked(createFreeKey).mockResolvedValue({ key: "free-key-123", tier: "free", email: "test@test.com", createdAt: "" });
-  vi.mocked(createVerification).mockResolvedValue({ email: "test@test.com", token: "tok", apiKey: "free-key-123", createdAt: "", verifiedAt: null });
+
   vi.mocked(sendVerificationEmail).mockResolvedValue(true);
 
   const { signupRouter } = await import("../routes/signup.js");