feat: implement skills marketplace API with CRUD operations and gateway integration

backend/app/schemas/skills_marketplace.py

@@ -0,0 +1,49 @@
+"""Schemas for skills marketplace listing and install/uninstall actions."""
+
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID
+
+from pydantic import AnyHttpUrl
+from sqlmodel import SQLModel
+
+from app.schemas.common import NonEmptyStr
+
+RUNTIME_ANNOTATION_TYPES = (datetime, UUID, NonEmptyStr)
+
+
+class MarketplaceSkillCreate(SQLModel):
+    """Payload used to register a skill URL in the organization marketplace."""
+
+    source_url: AnyHttpUrl
+    name: NonEmptyStr | None = None
+    description: str | None = None
+
+
+class MarketplaceSkillRead(SQLModel):
+    """Serialized marketplace skill catalog record."""
+
+    id: UUID
+    organization_id: UUID
+    name: str
+    description: str | None = None
+    source_url: str
+    created_at: datetime
+    updated_at: datetime
+
+
+class MarketplaceSkillCardRead(MarketplaceSkillRead):
+    """Marketplace card payload with gateway-specific install state."""
+
+    installed: bool
+    installed_at: datetime | None = None
+
+
+class MarketplaceSkillActionResponse(SQLModel):
+    """Install/uninstall action response payload."""
+
+    ok: bool = True
+    skill_id: UUID
+    gateway_id: UUID
+    installed: bool