feat(api): add currency extraction and account name updates

- Extract currency from balances and populate account currency field
- Add PUT /api/v1/accounts/{account_id} endpoint for updating account names
- Add AccountUpdate Pydantic model for request validation
- Modify sync service to enrich account details with balance currency

This resolves the issue where account currency and name fields were NULL
by extracting currency from GoCardless balance data and providing an API
endpoint for manual account name updates.

leggend/api/models/accounts.py

@@ -33,6 +33,15 @@ class AccountDetails(BaseModel):
         json_encoders = {datetime: lambda v: v.isoformat() if v else None}
 
 
+class AccountUpdate(BaseModel):
+    """Account update model"""
+
+    name: Optional[str] = None
+
+    class Config:
+        json_encoders = {datetime: lambda v: v.isoformat() if v else None}
+
+
 class Transaction(BaseModel):
     """Transaction model"""
 

leggend/api/routes/accounts.py

@@ -8,6 +8,7 @@ from leggend.api.models.accounts import (
     AccountBalance,
     Transaction,
     TransactionSummary,
+    AccountUpdate,
 )
 from leggend.services.database_service import DatabaseService
 
@@ -287,3 +288,40 @@ async def get_account_transactions(
         raise HTTPException(
             status_code=404, detail=f"Failed to get transactions: {str(e)}"
         ) from e
+
+
+@router.put("/accounts/{account_id}", response_model=APIResponse)
+async def update_account_details(
+    account_id: str, update_data: AccountUpdate
+) -> APIResponse:
+    """Update account details (currently only name)"""
+    try:
+        # Get current account details
+        current_account = await database_service.get_account_details_from_db(account_id)
+
+        if not current_account:
+            raise HTTPException(
+                status_code=404, detail=f"Account {account_id} not found"
+            )
+
+        # Prepare updated account data
+        updated_account_data = current_account.copy()
+        if update_data.name is not None:
+            updated_account_data["name"] = update_data.name
+
+        # Persist updated account details
+        await database_service.persist_account_details(updated_account_data)
+
+        return APIResponse(
+            success=True,
+            data={"id": account_id, "name": update_data.name},
+            message=f"Account {account_id} name updated successfully",
+        )
+
+    except HTTPException:
+        raise
+    except Exception as e:
+        logger.error(f"Failed to update account {account_id}: {e}")
+        raise HTTPException(
+            status_code=500, detail=f"Failed to update account: {str(e)}"
+        ) from e