feat(core): add tax rate schemas

app/schemas/tax.py

@@ -0,0 +1,34 @@
+"""Tax rate schemas — create, update, read, list."""
+
+from __future__ import annotations
+
+from pydantic import BaseModel, Field
+
+
+class TaxRateCreate(BaseModel):
+    name: str = Field(..., min_length=1, max_length=100)
+    rate: float = Field(..., ge=0, le=100)
+    is_default: bool = False
+    country: str | None = Field(None, max_length=2)
+
+
+class TaxRateUpdate(BaseModel):
+    name: str | None = Field(None, min_length=1, max_length=100)
+    rate: float | None = Field(None, ge=0, le=100)
+    is_default: bool | None = None
+    country: str | None = Field(None, max_length=2)
+
+
+class TaxRateResponse(BaseModel):
+    id: str
+    name: str
+    rate: float
+    is_default: bool
+    country: str | None = None
+    created_at: str | None = None
+    updated_at: str | None = None
+
+
+class TaxRateListResponse(BaseModel):
+    items: list[TaxRateResponse]
+    total: int