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

backend/app/models/marketplace_skills.py

@@ -0,0 +1,35 @@
+"""Organization-scoped skill catalog entries for the skills marketplace."""
+
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID, uuid4
+
+from sqlalchemy import UniqueConstraint
+from sqlmodel import Field
+
+from app.core.time import utcnow
+from app.models.tenancy import TenantScoped
+
+RUNTIME_ANNOTATION_TYPES = (datetime,)
+
+
+class MarketplaceSkill(TenantScoped, table=True):
+    """A marketplace skill entry that can be installed onto one or more gateways."""
+
+    __tablename__ = "marketplace_skills"  # pyright: ignore[reportAssignmentType]
+    __table_args__ = (
+        UniqueConstraint(
+            "organization_id",
+            "source_url",
+            name="uq_marketplace_skills_org_source_url",
+        ),
+    )
+
+    id: UUID = Field(default_factory=uuid4, primary_key=True)
+    organization_id: UUID = Field(foreign_key="organizations.id", index=True)
+    name: str
+    description: str | None = Field(default=None)
+    source_url: str
+    created_at: datetime = Field(default_factory=utcnow)
+    updated_at: datetime = Field(default_factory=utcnow)