1.3.6 Toast Notification Pattern: Add centralized ToastService abstraction

- Create ToastService extending BaseService with context-specific toast methods
- Add useToast composable for convenient dependency injection access
- Provide standardized toast patterns: auth, payment, clipboard, operations
- Include async operation support with automatic loading/success/error states
- Integrate with DI container and base module for automatic initialization
- Demonstrate refactoring in LoginDialog.vue with context-specific methods
- Eliminate duplicate vue-sonner imports across 20+ files for better maintainability
- Support custom ToastOptions interface with full TypeScript compatibility

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/components/auth/LoginDialog.vue

@@ -8,7 +8,7 @@ import { Input } from '@/components/ui/input'
 import { Label } from '@/components/ui/label'
 import { User } from 'lucide-vue-next'
 import { auth } from '@/composables/useAuth'
-import { toast } from 'vue-sonner'
+import { useToast } from '@/core/composables/useToast'
 
 interface Props {
   isOpen: boolean
@@ -20,6 +20,7 @@ interface Emits {
 }
 
 const router = useRouter()
+const toast = useToast()
 defineProps<Props>()
 const emit = defineEmits<Emits>()
 
@@ -63,14 +64,14 @@ async function handleLogin() {
       password: loginForm.value.password
     })
 
-    toast.success('Login successful!')
+    toast.auth.loginSuccess()
     emit('success')
     handleClose()
     // Redirect to home page after successful login
     router.push('/')
   } catch (err) {
     error.value = err instanceof Error ? err.message : 'Login failed'
-    toast.error('Login failed. Please check your credentials.')
+    toast.auth.loginError()
   } finally {
     isLoading.value = false
   }
@@ -90,14 +91,14 @@ async function handleRegister() {
       password_repeat: registerForm.value.password_repeat
     })
 
-    toast.success('Registration successful!')
+    toast.auth.registrationSuccess()
     emit('success')
     handleClose()
     // Redirect to home page after successful registration
     router.push('/')
   } catch (err) {
     error.value = err instanceof Error ? err.message : 'Registration failed'
-    toast.error('Registration failed. Please try again.')
+    toast.auth.registrationError()
   } finally {
     isLoading.value = false
   }