Create Schema

Create a new resource schema version.

Issue #276: Owner-only access via WorkspaceOwner dependency.

Args: resource_id: Resource identifier request: Schema creation request owner: Workspace owner (user_id, workspace_id) from dependency db: Database session

Returns: Created schema

Raises: 403: Not workspace owner 400: Invalid resource_id or schema definition 404: No such resource in the caller's workspace 409: The resource has no live context (#1877)

Notes: - Automatically increments schema_version - Only workspace owners can create schemas - Triggers rebuild for all contexts using this resource (TODO: Week 4)

Example: POST /api/v1/resources/ec_products/schema Body: { "resource_id": "ec_products", "field_definitions": [ { "name": "product_name", "type": "text", "description": "商品名", "classification": "public", "index_hint": "fulltext+vector", "required": true }, { "name": "price", "type": "number", "description": "価格（税込）", "unit": "JPY", "index_hint": "sort+facet" } ] }