refactor: move sector phase persistence to heaven repository

app/backend/features/heaven/repository.py

@@ -7,6 +7,35 @@ from typing import Any
 
 
 class HeavenRepositoryMixin:
+    def list_sector_phase_overrides(self) -> dict[str, str]:
+        with self.connect() as connection:
+            rows = connection.execute(
+                "SELECT name, element FROM sector_phase_overrides ORDER BY updated_at DESC, name"
+            ).fetchall()
+        return {row["name"]: row["element"] for row in rows}
+
+    def save_sector_phase_override(self, name: str, element: str) -> None:
+        now = datetime.now().astimezone().isoformat(timespec="seconds")
+        with self.connect() as connection:
+            connection.execute(
+                """
+                INSERT INTO sector_phase_overrides (name, element, updated_at)
+                VALUES (?, ?, ?)
+                ON CONFLICT(name) DO UPDATE SET
+                    element = excluded.element,
+                    updated_at = excluded.updated_at
+                """,
+                (name, element, now),
+            )
+
+    def delete_sector_phase_override(self, name: str) -> bool:
+        with self.connect() as connection:
+            cursor = connection.execute(
+                "DELETE FROM sector_phase_overrides WHERE name = ?",
+                (name,),
+            )
+            return cursor.rowcount > 0
+
     @staticmethod
     def _heaven_reading_dict(row: sqlite3.Row | None) -> dict[str, Any] | None:
         if not row: