feat: billing and credit management v2 (#429)

* feat: use mps generated correlation ID

* chore: update pipecat submodule

* feat: add credit purchase URL

* feat: carve out billing page and show credit ledger

* feat: deprecate dograh based quota tracking

* fix: remove cost calculation from dograh codebase

* fix: create mps account on migrate to v2

* chore: update pipecat

api/tests/test_organization_usage_billing.py

@@ -0,0 +1,99 @@
+from types import SimpleNamespace
+from unittest.mock import AsyncMock
+
+import pytest
+
+from api.routes import organization_usage
+
+
+def test_is_mps_billing_v2_depends_only_on_account_mode():
+    assert organization_usage._is_mps_billing_v2({"billing_mode": "v2"}) is True
+    assert organization_usage._is_mps_billing_v2({"billing_mode": "v1"}) is False
+    assert organization_usage._is_mps_billing_v2({"billing_mode": "shadow"}) is False
+    assert organization_usage._is_mps_billing_v2(None) is False
+
+
+@pytest.mark.asyncio
+async def test_get_mps_billing_account_status_uses_user_provider_id(monkeypatch):
+    get_status = AsyncMock(return_value={"billing_mode": "v2"})
+    monkeypatch.setattr(
+        organization_usage.mps_service_key_client,
+        "get_billing_account_status",
+        get_status,
+    )
+
+    user = SimpleNamespace(provider_id="provider-123")
+
+    assert await organization_usage._get_mps_billing_account_status(user, 42) == {
+        "billing_mode": "v2"
+    }
+    get_status.assert_awaited_once_with(
+        organization_id=42,
+        created_by="provider-123",
+    )
+
+
+@pytest.mark.asyncio
+async def test_get_billing_credits_pages_v2_ledger(monkeypatch):
+    monkeypatch.setattr(organization_usage, "DEPLOYMENT_MODE", "saas")
+    monkeypatch.setattr(
+        organization_usage,
+        "_get_mps_billing_account_status",
+        AsyncMock(return_value={"billing_mode": "v2"}),
+    )
+    get_ledger = AsyncMock(
+        return_value={
+            "account": {
+                "id": 7,
+                "organization_id": 42,
+                "billing_mode": "v2",
+                "cached_balance_credits": 250,
+                "currency": "USD",
+            },
+            "ledger_entries": [
+                {
+                    "id": 99,
+                    "entry_type": "grant",
+                    "origin": "account_creation",
+                    "credits_delta": 250,
+                    "balance_after": 250,
+                    "created_at": "2026-06-12T00:00:00Z",
+                }
+            ],
+            "total_debits_credits": 75,
+            "total_count": 101,
+            "page": 3,
+            "limit": 25,
+            "total_pages": 5,
+        }
+    )
+    monkeypatch.setattr(
+        organization_usage.mps_service_key_client,
+        "get_credit_ledger",
+        get_ledger,
+    )
+
+    user = SimpleNamespace(
+        provider_id="provider-123",
+        selected_organization_id=42,
+    )
+
+    response = await organization_usage.get_billing_credits(
+        page=3,
+        limit=25,
+        user=user,
+    )
+
+    get_ledger.assert_awaited_once_with(
+        organization_id=42,
+        page=3,
+        limit=25,
+        created_by="provider-123",
+    )
+    assert response.billing_version == "v2"
+    assert response.total_credits_used == 75
+    assert response.total_count == 101
+    assert response.page == 3
+    assert response.limit == 25
+    assert response.total_pages == 5
+    assert response.ledger_entries[0].id == 99