feat: add PSA ticket context Pydantic schemas (Task 6)

Add TicketDetails, CompanyInfo, ContactInfo, ConfigItem, TicketNote,
RelatedTicket, and TicketContext models in schemas/psa_context.py for
structured ticket context enrichment used by AI prompt injection.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/schemas/psa_context.py

@@ -0,0 +1,68 @@
+"""Pydantic schemas for PSA ticket context enrichment."""
+from __future__ import annotations
+
+from datetime import datetime
+
+from pydantic import BaseModel
+
+
+class TicketDetails(BaseModel):
+    id: int
+    summary: str
+    status: str
+    priority: str
+    board: str
+    sla: str | None = None
+    date_entered: datetime
+    resources: str | None = None
+
+
+class CompanyInfo(BaseModel):
+    id: int
+    name: str
+    site: str | None = None
+    address: str | None = None
+    phone: str | None = None
+    type: str | None = None
+    territory: str | None = None
+
+
+class ContactInfo(BaseModel):
+    name: str
+    email: str | None = None
+    phone: str | None = None
+    title: str | None = None
+
+
+class ConfigItem(BaseModel):
+    device_identifier: str
+    type: str | None = None
+    os_type: str | None = None
+    serial_number: str | None = None
+    ip_address: str | None = None
+    model_number: str | None = None
+
+
+class TicketNote(BaseModel):
+    text: str
+    member: str | None = None
+    date_created: datetime
+    internal_analysis_flag: bool = False
+
+
+class RelatedTicket(BaseModel):
+    id: int
+    summary: str
+    status: str
+    priority: str
+    board: str
+
+
+class TicketContext(BaseModel):
+    ticket: TicketDetails
+    company: CompanyInfo
+    contact: ContactInfo | None = None
+    configurations: list[ConfigItem] = []
+    notes: list[TicketNote] = []
+    related_tickets: list[RelatedTicket] = []
+    fetched_at: datetime