Feat: add forgot password reset, solve #8547 (#10586)

### What problem does this PR solve?

Feat: add forgot password reset, solve #8547

### Type of change

- [X] New Feature (non-breaking change which adds functionality)

api/utils/email_templates.py

@@ -0,0 +1,25 @@
+"""
+Reusable HTML email templates and registry.
+"""
+
+# Invitation email template
+INVITE_EMAIL_TMPL = """
+<p>Hi {{email}},</p>
+<p>{{inviter}} has invited you to join their team (ID: {{tenant_id}}).</p>
+<p>Click the link below to complete your registration:<br>
+<a href="{{invite_url}}">{{invite_url}}</a></p>
+<p>If you did not request this, please ignore this email.</p>
+"""
+
+# Password reset code template
+RESET_CODE_EMAIL_TMPL = """
+<p>Hello,</p>
+<p>Your password reset code is: <b>{{ code }}</b></p>
+<p>This code will expire in {{ ttl_min }} minutes.</p>
+"""
+
+# Template registry
+EMAIL_TEMPLATES = {
+    "invite": INVITE_EMAIL_TMPL,
+    "reset_code": RESET_CODE_EMAIL_TMPL,
+}