refactor: fix dependency injection in UserManager event handlers

[Besthope-Official]

Use Case

UserManager.on_after_reset_password() directly imports infrastructure dependencies, creating tight coupling and making testing difficult.

Proposed Solution

Inject RefreshTokenManager via constructor:

# Before (src/auth/manager.py:43-50)
async def on_after_reset_password(self, user: User, request: Request | None = None):
    from src.cache import cache  # ❌ Direct import
    refresh_manager = RefreshTokenManager(cache, self.settings)
    await refresh_manager.revoke_all_user_tokens(user.id)

# After
class UserManager(BaseUserManager):
    def __init__(self, ..., refresh_manager: RefreshTokenManager):
        self.refresh_manager = refresh_manager
    
    async def on_after_reset_password(self, ...):
        await self.refresh_manager.revoke_all_user_tokens(user.id)  # ✅ Injected

Alternatives Considered

N/A - Dependency injection is the standard solution for this pattern.

Implementation Notes

• Affected file: src/auth/manager.py:43-50
• Update get_user_manager() dependency function to inject RefreshTokenManager
• Improves testability and follows dependency inversion principle