feat(schemas): add meal plan Pydantic models

app/models/schemas/meal_plan.py

@@ -0,0 +1,87 @@
+# app/models/schemas/meal_plan.py
+"""Pydantic schemas for meal planning endpoints."""
+from __future__ import annotations
+
+from pydantic import BaseModel, Field
+
+
+VALID_MEAL_TYPES = {"breakfast", "lunch", "dinner", "snack"}
+
+
+class CreatePlanRequest(BaseModel):
+    week_start: str  # ISO date string, e.g. "2026-04-14" (must be Monday)
+    meal_types: list[str] = Field(default_factory=lambda: ["dinner"])
+
+
+class UpsertSlotRequest(BaseModel):
+    recipe_id: int | None = None
+    servings: float = Field(2.0, gt=0)
+    custom_label: str | None = None
+
+
+class SlotSummary(BaseModel):
+    id: int
+    plan_id: int
+    day_of_week: int
+    meal_type: str
+    recipe_id: int | None
+    recipe_title: str | None
+    servings: float
+    custom_label: str | None
+
+
+class PlanSummary(BaseModel):
+    id: int
+    week_start: str
+    meal_types: list[str]
+    slots: list[SlotSummary]
+    created_at: str
+
+
+class RetailerLink(BaseModel):
+    retailer: str
+    label: str
+    url: str
+
+
+class GapItem(BaseModel):
+    ingredient_name: str
+    needed_raw: str | None      # e.g. "2 cups" from recipe text
+    have_quantity: float | None  # from pantry
+    have_unit: str | None
+    covered: bool               # True = pantry has it
+    retailer_links: list[RetailerLink] = Field(default_factory=list)
+
+
+class ShoppingListResponse(BaseModel):
+    plan_id: int
+    gap_items: list[GapItem]
+    covered_items: list[GapItem]
+    disclosure: str | None = None  # affiliate disclosure text when links present
+
+
+class PrepTaskSummary(BaseModel):
+    id: int
+    recipe_id: int | None
+    task_label: str
+    duration_minutes: int | None
+    sequence_order: int
+    equipment: str | None
+    is_parallel: bool
+    notes: str | None
+    user_edited: bool
+
+
+class PrepSessionSummary(BaseModel):
+    id: int
+    plan_id: int
+    scheduled_date: str
+    status: str
+    tasks: list[PrepTaskSummary]
+
+
+class UpdatePrepTaskRequest(BaseModel):
+    duration_minutes: int | None = None
+    sequence_order: int | None = None
+    notes: str | None = None
+    equipment: str | None = None