Add Other Purchases to budget page

- New other_purchases table (date, total, notes)
- /api/other CRUD endpoints
- Budget stats now include other costs in cost/egg and cost/dozen math
- Budget page: new Log Other Purchases form, stat cards for other costs,
  combined Purchase History table showing feed and other entries together

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/schemas.py

@@ -73,6 +73,28 @@ class FeedPurchaseOut(BaseModel):
     model_config = {"from_attributes": True}
 
 
+# ── Other Purchases ───────────────────────────────────────────────────────────
+
+class OtherPurchaseCreate(BaseModel):
+    date:  date
+    total: Decimal = Field(gt=0, decimal_places=2)
+    notes: Optional[str] = None
+
+class OtherPurchaseUpdate(BaseModel):
+    date:  Optional[date]    = None
+    total: Optional[Decimal] = Field(default=None, gt=0, decimal_places=2)
+    notes: Optional[str]     = None
+
+class OtherPurchaseOut(BaseModel):
+    id:         int
+    date:       date
+    total:      Decimal
+    notes:      Optional[str]
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
 # ── Stats ─────────────────────────────────────────────────────────────────────
 
 class MonthlySummary(BaseModel):
@@ -85,6 +107,7 @@ class MonthlySummary(BaseModel):
     flock_at_month_end:     Optional[int]
     avg_eggs_per_hen_per_day: Optional[float]
     feed_cost:              Optional[Decimal]
+    other_cost:             Optional[Decimal]
     cost_per_egg:           Optional[Decimal]
     cost_per_dozen:         Optional[Decimal]
 
@@ -99,11 +122,13 @@ class DashboardStats(BaseModel):
     days_tracked:             int
 
 class BudgetStats(BaseModel):
-    total_feed_cost:     Optional[Decimal]
-    total_feed_cost_30d: Optional[Decimal]
-    total_eggs_alltime:  int
-    total_eggs_30d:      int
-    cost_per_egg:        Optional[Decimal]
-    cost_per_dozen:      Optional[Decimal]
-    cost_per_egg_30d:    Optional[Decimal]
-    cost_per_dozen_30d:  Optional[Decimal]
+    total_feed_cost:      Optional[Decimal]
+    total_feed_cost_30d:  Optional[Decimal]
+    total_other_cost:     Optional[Decimal]
+    total_other_cost_30d: Optional[Decimal]
+    total_eggs_alltime:   int
+    total_eggs_30d:       int
+    cost_per_egg:         Optional[Decimal]
+    cost_per_dozen:       Optional[Decimal]
+    cost_per_egg_30d:     Optional[Decimal]
+    cost_per_dozen_30d:   Optional[Decimal]