feat: add reusable solution library

backend/apps/solutions/schemas.py

@@ -0,0 +1,44 @@
+from datetime import datetime
+
+from ninja import Schema
+
+
+class SolutionIn(Schema):
+    title: str
+    problem_signature: str
+    related_system: str = ""
+    environment_scope: str = ""
+    root_cause: str
+    solution: str
+    risk_note: str = ""
+    status: str = "draft"
+
+
+class SolutionOut(Schema):
+    id: int
+    title: str
+    problem_signature: str
+    related_system: str
+    environment_scope: str
+    root_cause: str
+    solution: str
+    risk_note: str
+    status: str
+    usage_count: int
+    created_at: datetime
+    updated_at: datetime
+
+
+class TicketSolutionLinkIn(Schema):
+    ticket_id: int
+    link_type: str = "referenced"
+    agent_run_id: int | None = None
+
+
+class TicketSolutionLinkOut(Schema):
+    id: int
+    ticket_id: int
+    solution_id: int
+    link_type: str
+    solution_usage_count: int
+    created_at: datetime