feat: add Pydantic schemas for PSA connection CRUD

PsaConnectionCreate, PsaConnectionUpdate, PsaConnectionResponse,
and PsaConnectionTestResponse — registered in schemas __init__.

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

backend/app/schemas/__init__.py

@@ -15,6 +15,9 @@ from .script_template import (
     ScriptTemplateCreate, ScriptTemplateUpdate, ScriptTemplateListItem, ScriptTemplateDetail,
     ScriptGenerateRequest, ScriptGenerateResponse, ScriptGenerationRecord,
 )
+from .psa_connection import (
+    PsaConnectionCreate, PsaConnectionUpdate, PsaConnectionResponse, PsaConnectionTestResponse,
+)
 
 __all__ = [
     # User
@@ -39,4 +42,6 @@ __all__ = [
     "ScriptCategoryResponse",
     "ScriptTemplateCreate", "ScriptTemplateUpdate", "ScriptTemplateListItem", "ScriptTemplateDetail",
     "ScriptGenerateRequest", "ScriptGenerateResponse", "ScriptGenerationRecord",
+    # PSA Connection
+    "PsaConnectionCreate", "PsaConnectionUpdate", "PsaConnectionResponse", "PsaConnectionTestResponse",
 ]

backend/app/schemas/psa_connection.py

@@ -0,0 +1,47 @@
+"""Pydantic schemas for PSA connection management."""
+from __future__ import annotations
+from datetime import datetime
+from uuid import UUID
+from pydantic import BaseModel, Field
+
+
+class PsaConnectionCreate(BaseModel):
+    provider: str = Field(default="connectwise", pattern="^(connectwise|autotask)$")
+    display_name: str = Field(min_length=1, max_length=100)
+    site_url: str = Field(min_length=1, max_length=255)
+    company_id: str = Field(min_length=1, max_length=100)
+    public_key: str = Field(min_length=1)
+    private_key: str = Field(min_length=1)
+    client_id: str = Field(min_length=1)
+
+
+class PsaConnectionUpdate(BaseModel):
+    display_name: str | None = None
+    site_url: str | None = None
+    company_id: str | None = None
+    public_key: str | None = None
+    private_key: str | None = None
+    client_id: str | None = None
+
+
+class PsaConnectionResponse(BaseModel):
+    id: UUID
+    account_id: UUID
+    provider: str
+    display_name: str
+    site_url: str
+    company_id: str
+    is_active: bool
+    last_validated_at: datetime | None
+    created_at: datetime
+    updated_at: datetime
+    public_key_hint: str
+    private_key_hint: str
+
+    model_config = {"from_attributes": True}
+
+
+class PsaConnectionTestResponse(BaseModel):
+    success: bool
+    message: str
+    server_version: str | None = None