fix(10): revise plans based on checker feedback

- Plan 10-02: Added explicit UserMailService wiring in Account.scala
  onRegister handler for activation emails when activateMode == User
- Plan 10-04: Split into backend-only (models, services, admin controller)
  reducing from 16 to 15 files, estimated context ~50%
- Plan 10-05: New plan for frontend components (Posts, Post, Categories,
  RelatedPosts), Wave 3 depends on 10-04
- Updated ROADMAP.md to reflect 5 plans for Phase 10

.planning/phases/10-core-plugins/10-02-PLAN.md

@@ -6,6 +6,7 @@ wave: 2
 depends_on: ["10-01"]
 files_modified:
   - plugins/golem15/user/components/ResetPassword.scala
+  - plugins/golem15/user/components/Account.scala
   - plugins/golem15/user/services/FrontendUserService.scala
   - plugins/golem15/user/services/UserMailService.scala
   - plugins/golem15/user/resources/views/account/profile.peb
@@ -155,6 +156,7 @@ Output: Working profile and reset features:
   <name>Task 2: Password reset flow and email service</name>
   <files>
     plugins/golem15/user/components/ResetPassword.scala
+    plugins/golem15/user/components/Account.scala (modify)
     plugins/golem15/user/services/UserMailService.scala
     plugins/golem15/user/services/FrontendUserService.scala (modify)
     plugins/golem15/user/resources/views/resetpassword/request.peb
@@ -175,6 +177,13 @@ Output: Working profile and reset features:
       - Send via configured SMTP or email service
     - MailError ADT: SendFailed, TemplateError, ConfigurationError
 
+    **Account.scala modification (CRITICAL - wire activation email):**
+    - Modify the onRegister handler created in Plan 01 to integrate UserMailService:
+      - Inject UserMailService dependency into Account component
+      - After successful userService.register call, check UserSettings.activateMode
+      - If activateMode == ActivateMode.User, call mailService.sendActivationEmail(user, activationCode)
+      - This completes the key_link from Account.scala to UserMailService
+
     **FrontendUserService.scala additions:**
     - requestPasswordReset(email: String): Unit
       - Find user by email (don't reveal if not found - timing attack)
@@ -230,13 +239,14 @@ Output: Working profile and reset features:
   <verify>
     ./mill summercms.compile succeeds
     ResetPassword component registered in Plugin.scala
+    Account.scala onRegister calls mailService.sendActivationEmail when activateMode == User
     Email templates have valid Pebble syntax
     Reset code generation uses SecureRandom
   </verify>
   <done>
     Password reset request sends email (or stubs if no SMTP).
     Reset link with token allows setting new password.
-    Activation email template ready for registration flow.
+    Activation email sent during registration when activateMode is User.
     No email enumeration possible (generic success messages).
   </done>
 </task>
@@ -247,9 +257,10 @@ Output: Working profile and reset features:
 After all tasks complete:
 1. User plugin compiles: `./mill summercms.compile`
 2. Account component has all handlers: onSignin, onRegister, onActivate, onUpdate, onUploadAvatar
-3. ResetPassword component handles: onRequest, onReset
-4. Email service can send activation and reset emails
-5. Templates render valid forms with HTMX
+3. Account.scala onRegister integrates UserMailService for activation emails
+4. ResetPassword component handles: onRequest, onReset
+5. Email service can send activation and reset emails
+6. Templates render valid forms with HTMX
 </verification>
 
 <success_criteria>
@@ -257,6 +268,7 @@ After all tasks complete:
 - Profile update saves name/surname changes
 - Password change requires current password confirmation
 - Avatar upload stores image and updates user record
+- Registration with activateMode=User triggers activation email via UserMailService
 - Password reset request always shows success (no enumeration)
 - Reset link with valid code allows new password entry
 - User automatically logged in after successful reset