feat: add ScriptBuilderSession model, migration, and schemas

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

backend/app/schemas/script_builder.py

@@ -0,0 +1,69 @@
+"""Pydantic schemas for the AI Script Builder."""
+from datetime import datetime
+from typing import Any, Optional
+from uuid import UUID
+
+from pydantic import BaseModel, Field
+
+
+class ScriptBuilderCreateRequest(BaseModel):
+    """Request to start a new builder session."""
+    language: str = Field(
+        default="powershell",
+        pattern=r"^(powershell|bash|python)$",
+        description="Script language",
+    )
+
+
+class ScriptBuilderMessageRequest(BaseModel):
+    """User message in a builder session."""
+    content: str = Field(min_length=1, max_length=5000)
+
+
+class ScriptBuilderMessageResponse(BaseModel):
+    """AI response to a builder message."""
+    role: str = "assistant"
+    content: str
+    script: str | None = None
+    script_filename: str | None = None
+    line_count: int | None = None
+    timestamp: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class ScriptBuilderSessionSummary(BaseModel):
+    """Lightweight session for list views (no messages)."""
+    id: UUID
+    language: str
+    title: str | None = None
+    message_count: int
+    latest_script_filename: str | None = None
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class ScriptBuilderSessionDetail(BaseModel):
+    """Full session with message history."""
+    id: UUID
+    language: str
+    title: str | None = None
+    messages: list[dict[str, Any]]
+    latest_script: str | None = None
+    latest_script_filename: str | None = None
+    message_count: int
+    ai_session_id: UUID | None = None
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class SaveToLibraryRequest(BaseModel):
+    """Request to save a generated script to the Script Library."""
+    name: str = Field(min_length=1, max_length=200)
+    description: str | None = None
+    category_id: UUID | None = None
+    share_with_team: bool = False