feat(privacy): add personalized ads toggle in settings

- Add PrivacySettings schema with can_sell field (default: false)
- Move privacy toggle to GeneralSettingsScreen with clear labeling
- Update l10n for zh/en/zh_hant with user-friendly copy
- Clean up redundant PrivacyNotificationSettingsScreen
- Update profile-protocol.md to reflect new privacy schema
- Fix basedpyright warnings in user.py

backend/src/schemas/shared/user.py

@@ -27,7 +27,7 @@ class PreferenceSettings(BaseModel):
     @classmethod
     def validate_timezone(cls, value: str) -> str:
         try:
-            ZoneInfo(value)
+            _ = ZoneInfo(value)
         except ZoneInfoNotFoundError as exc:
             raise ValueError("timezone must be a valid IANA timezone") from exc
         return value
@@ -52,10 +52,15 @@ class DivinationTutorialSettings(BaseModel):
     manual_divination_shown: bool = False
 
 
+class PrivacySettings(BaseModel):
+    can_sell: bool = False
+    profile_visibility: str = "public"
+
+
 class ProfileSettingsV1(BaseModel):
     version: Literal[1] = 1
     preferences: PreferenceSettings = Field(default_factory=PreferenceSettings)
-    privacy: dict[str, object] = Field(default_factory=dict)
+    privacy: PrivacySettings = Field(default_factory=PrivacySettings)
     notification: NotificationSettings = Field(default_factory=NotificationSettings)
     divination_tutorial: DivinationTutorialSettings = Field(
         default_factory=DivinationTutorialSettings
@@ -67,7 +72,13 @@ ProfileSettingsUnion = ProfileSettingsV1
 
 def parse_profile_settings(raw: dict[str, object] | None) -> ProfileSettingsUnion:
     payload = dict(raw or {})
-    payload.setdefault("version", 1)
+    _ = payload.setdefault("version", 1)
+
+    if "privacy" in payload:
+        privacy_data = payload["privacy"]
+        if isinstance(privacy_data, dict):
+            payload["privacy"] = PrivacySettings.model_validate(privacy_data)
+
     return ProfileSettingsV1.model_validate(payload)
 
 
@@ -76,7 +87,7 @@ def upgrade_to_latest(settings: ProfileSettingsUnion) -> ProfileSettingsV1:
 
 
 class UserContext(BaseModel):
-    model_config = ConfigDict(from_attributes=True)
+    model_config = ConfigDict(from_attributes=True)  # pyright: ignore[reportUnannotatedClassAttribute]
 
     id: str
     username: str