fix(cost-center): the billing module does not calculate LLMToken consumption

[jockey-x]

Fix LLMToken cost consistency in consumption APIs

Problem

The getTotalAppCost() method already includes LLMToken fees, but GetConsumptionAmount() and GetWorkspaceConsumptionAmount() only query app_costs.amount, missing the amount field for LLMToken and AppStore types. This causes inconsistent data between the appOverview
endpoint and the consumption endpoints.

Solution

Modified GetConsumptionAmount() and GetWorkspaceConsumptionAmount() in service/account/dao/interface.go to use MongoDB's $facet operator, which queries both:

1. app_costs.amount - for regular applications (sub-consumption type)
2. amount field - for AppStore and LLMToken types (direct consumption)

Changes

• Updated GetConsumptionAmount() to aggregate both cost types and return the sum
• Updated GetWorkspaceConsumptionAmount() to merge results from both cost types, grouped by namespace

Impact

• /api/billing/consumption now includes LLMToken costs in the total amount
• /api/billing/workspace-consumption now includes LLMToken costs per workspace
• Data consistency is maintained across all billing-related endpoints

[cla-assistant]

All committers have signed the CLA.