feat(user): implement user restrictions

## APIs Restricted for Restricted Users

A restricted user is blocked from performing the following actions, and will typically receive a `403 Forbidden` error:

*   **Chat & Notifications:**
    *   Sending any chat messages (public or private).
    *   Joining or leaving chat channels.
    *   Creating new PM channels.
*   **User Profile & Content:**
    *   Uploading a new avatar.
    *   Uploading a new profile cover image.
    *   Changing their username.
    *   Updating their userpage content.
*   **Scores & Gameplay:**
    *   Submitting scores in multiplayer rooms.
    *   Deleting their own scores (to prevent hiding evidence of cheating).
*   **Beatmaps:**
    *   Rating beatmaps.
    *   Taging beatmaps.
*   **Relationship:**
    *   Adding friends or blocking users.
    *   Removing friends or unblocking users.
*   **Teams:**
    *   Creating, updating, or deleting a team.
    *   Requesting to join a team.
    *   Handling join requests for a team they manage.
    *   Kicking a member from a team they manage.
*   **Multiplayer:**
    *   Creating or deleting multiplayer rooms.
    *   Joining or leaving multiplayer rooms.

## What is Invisible to Normal Users

*   **Leaderboards:**
    *   Beatmap leaderboards.
    *   Multiplayer (playlist) room leaderboards.
*   **User Search/Lists:**
    *   Restricted users will not appear in the results of the `/api/v2/users` endpoint.
    *   They will not appear in the list of a team's members.
*   **Relationship:**
    *   They will not appear in a user's friend list (`/friends`).
*   **Profile & History:**
    *   Attempting to view a restricted user's profile, events, kudosu history, or score history will result in a `404 Not Found` error, effectively making their profile invisible (unless the user viewing the profile is the restricted user themselves).
*   **Chat:**
    *   Normal users cannot start a new PM with a restricted user (they will get a `404 Not Found` error).
*   **Ranking:**
    *   Restricted users are excluded from any rankings.

### How to Restrict a User

Insert into `user_account_history` with `type=restriction`.

```sql
-- length is in seconds
INSERT INTO user_account_history (`description`, `length`, `permanent`, `timestamp`, `type`, `user_id`) VALUE ('some description', 86400, 0, '2025-10-05 01:00:00', 'RESTRICTION', 1);
```

---

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

migrations/versions/2025-10-05_425b91532cb4_user_remove_is_restricted.py

@@ -0,0 +1,41 @@
+"""user: remove is_restricted
+
+Revision ID: 425b91532cb4
+Revises: ee13ad926584
+Create Date: 2025-10-05 11:11:46.391414
+
+"""
+
+from collections.abc import Sequence
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import mysql
+
+# revision identifiers, used by Alembic.
+revision: str = "425b91532cb4"
+down_revision: str | Sequence[str] | None = "ee13ad926584"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column("lazer_users", "is_restricted")
+
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    # Step 1: Add the column as nullable
+    op.add_column(
+        "lazer_users", sa.Column("is_restricted", mysql.TINYINT(display_width=1), autoincrement=False, nullable=True)
+    )
+    # Step 2: Set a default value for all existing rows
+    op.execute("UPDATE lazer_users SET is_restricted = 0 WHERE is_restricted IS NULL")
+    # Step 3: Alter the column to be NOT NULL
+    op.alter_column("lazer_users", "is_restricted", nullable=False)
+    # ### end Alembic commands ###