Add account deletion, admin user removal, household deletion, grayed-out other-user chips (47 tests)

models.py

@@ -111,6 +111,19 @@ def count_household_users(household_id: int) -> int:
         ).fetchone()[0]
 
 
+def delete_household(household_id: int) -> None:
+    """Delete a household, all its users, and all their responses."""
+    with get_db() as db:
+        # Delete responses for all users in the household
+        db.execute(
+            "DELETE FROM responses WHERE user_id IN "
+            "(SELECT id FROM users WHERE household_id = ?)",
+            (household_id,),
+        )
+        db.execute("DELETE FROM users WHERE household_id = ?", (household_id,))
+        db.execute("DELETE FROM households WHERE id = ?", (household_id,))
+
+
 # ── Users ─────────────────────────────────────────────────────────────────────
 
 def get_user_by_id(user_id: int) -> dict | None:
@@ -143,6 +156,13 @@ def create_user(username: str, password_hash: str, household_id: int,
         return get_user_by_id(user_id)
 
 
+def delete_user(user_id: int) -> None:
+    """Delete a user and all their responses."""
+    with get_db() as db:
+        db.execute("DELETE FROM responses WHERE user_id = ?", (user_id,))
+        db.execute("DELETE FROM users WHERE id = ?", (user_id,))
+
+
 def get_household_users(household_id: int) -> list[dict]:
     """Return all users in a given household."""
     with get_db() as db: