TICKET-003: Daily log write path

- POST/PUT/DELETE /api/log, GET /api/log?date= with embedded food
- sort_order auto-appends per day; hard delete for log entries
- Soft-deleted foods rejected for new logs (404) but render in history
- Full suite green (87 passed)

backend/schemas.py

@@ -103,6 +103,30 @@ class LogEntryCreate(BaseModel):
     date: date  # client-supplied YYYY-MM-DD (spec §8.1 rule 8)
 
 
+class LogEntryUpdate(BaseModel):
+    """Schema for PUT /api/log/{id}. All fields optional — only supplied
+    fields are updated. Send {"meal_slot": null} to clear the slot."""
+    quantity: float | None = Field(default=None, gt=0)
+    meal_slot: MealSlot | None = None
+    sort_order: int | None = None
+
+
+class LogFoodRead(BaseModel):
+    """Embedded food reference in log entry responses (spec §3.3, §8.3 rule 1).
+    Includes name, brand, unit_type, and serving info so the frontend can render
+    log entries without N+1 lookups. Soft-deleted foods render here (§2.1)."""
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    name: str
+    brand: str | None
+    unit_type: UnitType
+    serving_size_g: float | None
+    serving_name: str | None
+    is_meal: bool
+    deleted_at: datetime | None
+
+
 class LogEntryRead(BaseModel):
     model_config = ConfigDict(from_attributes=True)
 
@@ -112,6 +136,7 @@ class LogEntryRead(BaseModel):
     quantity: float
     meal_slot: MealSlot | None
     sort_order: int
+    food: LogFoodRead
 
 
 # ── Targets ──────────────────────────────────────────────────────────────────