feat: automated appointment reminders via email (GRO-23)

Implements Phase 1 of groombook/groombook#4 — automated email reminders
for upcoming appointments, with booking confirmations sent immediately
on creation.

- **DB**: new `reminder_logs` table tracks sent reminders per appointment
  (unique on appointmentId+type prevents duplicates); `clients` gains
  `email_opt_out` boolean (migration 0004_reminder_logs)
- **Email service**: `apps/api/src/services/email.ts` — nodemailer SMTP
  transport (disabled when SMTP_HOST is unset, so self-hosted installs
  without email config are unaffected); confirmation and reminder email
  templates included
- **Reminder scheduler**: `apps/api/src/services/reminders.ts` — node-cron
  job runs every minute, checks for appointments in the upcoming reminder
  windows (default: 24 h and 2 h), sends emails for opted-in clients,
  and records sends in reminder_logs (idempotent via ON CONFLICT DO NOTHING)
- **Confirmation email**: sent fire-and-forget after successful appointment
  creation (both single and recurring); never blocks the API response
- **Config**: SMTP_HOST, SMTP_PORT, SMTP_SECURE, SMTP_USER, SMTP_PASS,
  SMTP_FROM, REMINDER_HOURS_EARLY, REMINDER_HOURS_LATE env vars documented
  in .env.example; all optional — feature is silently disabled without them
- **Types**: Client.emailOptOut field added to shared types package

Co-Authored-By: Paperclip <noreply@paperclip.ing>

pnpm-lock.yaml

@@ -28,6 +28,12 @@ importers:
       jose:
         specifier: ^5.9.6
         version: 5.10.0
+      node-cron:
+        specifier: ^3.0.3
+        version: 3.0.3
+      nodemailer:
+        specifier: ^6.9.16
+        version: 6.10.1
       openid-client:
         specifier: ^6.1.7
         version: 6.8.2
@@ -38,6 +44,12 @@ importers:
       '@types/node':
         specifier: ^22.10.7
         version: 22.19.15
+      '@types/node-cron':
+        specifier: ^3.0.11
+        version: 3.0.11
+      '@types/nodemailer':
+        specifier: ^6.4.17
+        version: 6.4.23
       eslint:
         specifier: ^9.18.0
         version: 9.39.4
@@ -1529,9 +1541,15 @@ packages:
   '@types/json-schema@7.0.15':
     resolution: {integrity: sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==}
 
+  '@types/node-cron@3.0.11':
+    resolution: {integrity: sha512-0ikrnug3/IyneSHqCBeslAhlK2aBfYek1fGo4bP4QnZPmiqSGRK+Oy7ZMisLWkesffJvQ1cqAcBnJC+8+nxIAg==}
+
   '@types/node@22.19.15':
     resolution: {integrity: sha512-F0R/h2+dsy5wJAUe3tAU6oqa2qbWY5TpNfL/RGmo1y38hiyO1w3x2jPtt76wmuaJI4DQnOBu21cNXQ2STIUUWg==}
 
+  '@types/nodemailer@6.4.23':
+    resolution: {integrity: sha512-aFV3/NsYFLSx9mbb5gtirBSXJnAlrusoKNuPbxsASWc7vrKLmIrTQRpdcxNcSFL3VW2A2XpeLEavwb2qMi6nlQ==}
+
   '@types/react-dom@19.2.3':
     resolution: {integrity: sha512-jp2L/eY6fn+KgVVQAOqYItbF0VY/YApe5Mz2F0aykSO8gx31bYCZyvSeYxCHKvzHG5eZjc+zyaS5BrBWya2+kQ==}
     peerDependencies:
@@ -2506,9 +2524,17 @@ packages:
   natural-compare@1.4.0:
     resolution: {integrity: sha512-OWND8ei3VtNC9h7V60qff3SVobHr996CTwgxubgyQYEpg290h9J0buyECNNJexkFm5sOajh5G116RYA1c8ZMSw==}
 
+  node-cron@3.0.3:
+    resolution: {integrity: sha512-dOal67//nohNgYWb+nWmg5dkFdIwDm8EpeGYMekPMrngV3637lqnX0lbUcCtgibHTz6SEz7DAIjKvKDFYCnO1A==}
+    engines: {node: '>=6.0.0'}
+
   node-releases@2.0.36:
     resolution: {integrity: sha512-TdC8FSgHz8Mwtw9g5L4gR/Sh9XhSP/0DEkQxfEFXOpiul5IiHgHan2VhYYb6agDSfp4KuvltmGApc8HMgUrIkA==}
 
+  nodemailer@6.10.1:
+    resolution: {integrity: sha512-Z+iLaBGVaSjbIzQ4pX6XV41HrooLsQ10ZWPUehGmuantvzWoDVBnmsdUcOIDM1t+yPor5pDhVlDESgOMEGxhHA==}
+    engines: {node: '>=6.0.0'}
+
   oauth4webapi@3.8.5:
     resolution: {integrity: sha512-A8jmyUckVhRJj5lspguklcl90Ydqk61H3dcU0oLhH3Yv13KpAliKTt5hknpGGPZSSfOwGyraNEFmofDYH+1kSg==}
 
@@ -2978,6 +3004,10 @@ packages:
   uri-js@4.4.1:
     resolution: {integrity: sha512-7rKUyy33Q1yc98pQ1DAmLtwX109F7TIfWlW1Ydo8Wl1ii1SeHieeh0HHfPeL2fMXK6z0s8ecKs9frCuLJvndBg==}
 
+  uuid@8.3.2:
+    resolution: {integrity: sha512-+NYs2QeMWy+GWFOEm9xnn6HCDp0l7QBD7ml8zLUmJ+93Q5NF0NocErnwkTkXVFNiX3/fpC6afS8Dhb/gz7R7eg==}
+    hasBin: true
+
   vite-node@3.2.4:
     resolution: {integrity: sha512-EbKSKh+bh1E1IFxeO0pg1n4dvoOTt0UDiXMd/qn++r98+jPO1xtJilvXldeuQ8giIB5IkpjCgMleHMNEsGH6pg==}
     engines: {node: ^18.0.0 || ^20.0.0 || >=22.0.0}
@@ -4401,10 +4431,16 @@ snapshots:
 
   '@types/json-schema@7.0.15': {}
 
+  '@types/node-cron@3.0.11': {}
+
   '@types/node@22.19.15':
     dependencies:
       undici-types: 6.21.0
 
+  '@types/nodemailer@6.4.23':
+    dependencies:
+      '@types/node': 22.19.15
+
   '@types/react-dom@19.2.3(@types/react@19.2.14)':
     dependencies:
       '@types/react': 19.2.14
@@ -5485,8 +5521,14 @@ snapshots:
 
   natural-compare@1.4.0: {}
 
+  node-cron@3.0.3:
+    dependencies:
+      uuid: 8.3.2
+
   node-releases@2.0.36: {}
 
+  nodemailer@6.10.1: {}
+
   oauth4webapi@3.8.5: {}
 
   object-inspect@1.13.4: {}
@@ -6006,6 +6048,8 @@ snapshots:
     dependencies:
       punycode: 2.3.1
 
+  uuid@8.3.2: {}
+
   vite-node@3.2.4(@types/node@22.19.15)(terser@5.46.1)(tsx@4.21.0):
     dependencies:
       cac: 6.7.14