settings: Add setting for marking resolved-topic notices as read.

This commit adds a new personal setting
`resolved_topic_notice_auto_read_policy` which controls how
resolved-topic notices are marked as read for a user.

Fixes #33599.

zerver/models/users.py

@@ -1,4 +1,5 @@
 from email.headerregistry import Address
+from enum import Enum
 from typing import TYPE_CHECKING, Any, Optional
 from uuid import uuid4
 
@@ -35,6 +36,13 @@ if TYPE_CHECKING:
     from zerver.models import Realm
 
 
+class ResolvedTopicNoticeAutoReadPolicyEnum(Enum):
+    # The case is used by Pydantic in the API
+    always = 1
+    except_followed = 2
+    never = 3
+
+
 class UserBaseSettings(models.Model):
     """This abstract class is the container for all preferences/personal
     settings for users that control the behavior of the application.
@@ -263,6 +271,12 @@ class UserBaseSettings(models.Model):
     )
     automatically_follow_topics_where_mentioned = models.BooleanField(default=True)
 
+    resolved_topic_notice_auto_read_policy = models.PositiveSmallIntegerField(
+        default=ResolvedTopicNoticeAutoReadPolicyEnum.except_followed.value,
+        db_default=ResolvedTopicNoticeAutoReadPolicyEnum.except_followed.value,
+    )
+    RESOLVED_TOPIC_NOTICE_AUTO_READ_POLICY_TYPES = list(ResolvedTopicNoticeAutoReadPolicyEnum)
+
     # Whether or not the user wants to sync their drafts.
     enable_drafts_synchronization = models.BooleanField(default=True)
 
@@ -364,6 +378,7 @@ class UserBaseSettings(models.Model):
         web_navigate_to_sent_message=bool,
         web_suggest_update_timezone=bool,
         hide_ai_features=bool,
+        resolved_topic_notice_auto_read_policy=ResolvedTopicNoticeAutoReadPolicyEnum,
     )
 
     modern_notification_settings = dict(