Removes legacy equity accounts

Removes generic equity accounts that are no longer necessary
due to the user-specific equity model introduced by the
castle extension. Specifically, it removes
"Equity:MemberEquity" and "Equity:RetainedEarnings" accounts.

migrations.py

@@ -516,3 +516,28 @@ async def m013_remove_parent_only_accounts(db):
         "DELETE FROM accounts WHERE name = :name",
         {"name": "Equity"}
     )
+
+
+async def m014_remove_legacy_equity_accounts(db):
+    """
+    Remove legacy generic equity accounts that don't fit the user-specific equity model.
+
+    The castle extension uses dynamic user-specific equity accounts (Equity:User-{user_id})
+    created automatically when granting equity eligibility. Generic equity accounts like
+    MemberEquity and RetainedEarnings are not needed.
+
+    Removes:
+    - Equity:MemberEquity
+    - Equity:RetainedEarnings
+    """
+    # Remove Equity:MemberEquity
+    await db.execute(
+        "DELETE FROM accounts WHERE name = :name",
+        {"name": "Equity:MemberEquity"}
+    )
+
+    # Remove Equity:RetainedEarnings
+    await db.execute(
+        "DELETE FROM accounts WHERE name = :name",
+        {"name": "Equity:RetainedEarnings"}
+    )