Extract emails into separate package with clean interface

- Create packages/emails/ with EmailClient interface abstraction
- Wrap Postmark ServerClient in adapter for clean typing
- Add createLoggingEmailClient for dev mode (logs to console)
- Split email templates into individual files with full test coverage
- Update api-server to use new package via context injection
- Remove EMAIL_DEV_MODE - now uses POSTMARK_API_KEY presence
- Delete apps/api-server/src/utils/email.ts

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

apps/api-server/src/procedures/auth/signup.ts

@@ -10,6 +10,7 @@ import type {
 import type { Kysely } from "kysely";
 import type { RPInfo } from "../../utils/webauthn.js";
 import { ORPCError } from "@orpc/server";
+import { sendVerificationEmail } from "@reviq/emails";
 import { verifyRegistrationResponse } from "@simplewebauthn/server";
 import {
   COOKIE_NAMES,
@@ -21,7 +22,6 @@ import {
   generateExpiry,
   generateSecureBase58Token,
 } from "../../utils/crypto.js";
-import { sendVerificationEmail } from "../../utils/email.js";
 import { getGeoInfo, getUserAgent } from "../../utils/geo.js";
 import { hashPassword, validatePassword } from "../../utils/password.js";
 import { createSession } from "../../utils/session.js";
@@ -300,8 +300,15 @@ export const signup = os.auth.signup.handler(async ({ input, context }) => {
     })
     .execute();
 
-  // Send verification email (stubbed)
-  await sendVerificationEmail(email, verificationToken);
+  // Send verification email
+  await sendVerificationEmail({
+    client: context.email.client,
+    fromAddress: context.email.fromAddress,
+    baseUrl: context.email.baseUrl,
+    email,
+    token: verificationToken,
+    expiryHours: 24,
+  });
 
   return { success: true };
 });