Add deferred transactions, revamp budget projections and UI

Adds deferred_to_next_cycle flag to transactions for billing cycle
bleed-over handling. Overhauls budget projection engine and refreshes
Budget page with improved monthly detail and transaction columns.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/api/v1/endpoints/budget.py

@@ -194,6 +194,11 @@ class ActualsBySource(BaseModel):
     count: int
 
 
+class CCCategorySpending(BaseModel):
+    category_name: str
+    amount: float
+
+
 class MonthlyDetailResponse(BaseModel):
     year: int
     month: int
@@ -207,6 +212,7 @@ class MonthlyDetailResponse(BaseModel):
     uncovered_actual: float
     gran_total_egresos: float
     net_balance: float
+    cc_by_category: list[CCCategorySpending]
 
 
 @router.get("/month/{year}/{month}", response_model=MonthlyDetailResponse)
@@ -230,6 +236,7 @@ def get_monthly_detail(
         uncovered_actual=data["uncovered_actual"],
         gran_total_egresos=data["gran_total_egresos"],
         net_balance=data["net_balance"],
+        cc_by_category=[CCCategorySpending(**c) for c in data["cc_by_category"]],
     )
 
 

backend/app/api/v1/endpoints/transactions.py

@@ -19,19 +19,11 @@ from app.models.models import (
     TransactionUpdate,
 )
 
+from app.services.budget_projection import get_cycle_range, get_previous_cycle
+
 router = APIRouter(prefix="/transactions", tags=["transactions"])
 
 
-def get_cycle_range(year: int, month: int) -> tuple[datetime, datetime]:
-    """Return (start, end) for billing cycle: month/18 to month+1/18."""
-    start = datetime(year, month, 18)
-    if month == 12:
-        end = datetime(year + 1, 1, 18)
-    else:
-        end = datetime(year, month + 1, 18)
-    return start, end
-
-
 class BillingCycle(BaseModel):
     year: int
     month: int
@@ -54,6 +46,7 @@ def auto_categorize(merchant: str, session: Session) -> Optional[int]:
 @router.get("/", response_model=list[TransactionRead])
 def list_transactions(
     source: Optional[TransactionSource] = None,
+    exclude_source: Optional[TransactionSource] = None,
     search: Optional[str] = None,
     category_id: Optional[int] = None,
     cycle_year: Optional[int] = None,
@@ -68,13 +61,32 @@ def list_transactions(
     query = select(Transaction)
     if source:
         query = query.where(Transaction.source == source)
+    if exclude_source:
+        query = query.where(Transaction.source != exclude_source)
     if category_id:
         query = query.where(Transaction.category_id == category_id)
     if search:
         query = query.where(col(Transaction.merchant).ilike(f"%{search}%"))
     if cycle_year and cycle_month:
         start, end = get_cycle_range(cycle_year, cycle_month)
-        query = query.where(Transaction.date >= start, Transaction.date < end)
+        prev_y, prev_m = get_previous_cycle(cycle_year, cycle_month)
+        prev_start, prev_end = get_cycle_range(prev_y, prev_m)
+        # Normal transactions in this cycle (not deferred) + deferred from previous cycle
+        from sqlalchemy import or_, and_
+        query = query.where(
+            or_(
+                and_(
+                    Transaction.date >= start,
+                    Transaction.date < end,
+                    Transaction.deferred_to_next_cycle == False,  # noqa: E712
+                ),
+                and_(
+                    Transaction.date >= prev_start,
+                    Transaction.date < prev_end,
+                    Transaction.deferred_to_next_cycle == True,  # noqa: E712
+                ),
+            )
+        )
     elif start_date and end_date:
         query = query.where(
             Transaction.date >= datetime.fromisoformat(start_date),