T09: KI-Copilot API + Hybrid Workflow Engine + LLM client + event-triggered workflows

- KI-Copilot: NL query → proposed actions, execute with RBAC, history, audit logging
- LLM client: mock mode (no API key) + OpenAI-compatible mode (AI_MODEL/AI_API_KEY)
- Action mapper: NL intent → API calls (create/update/delete/search company/contact)
- Workflow engine: step types (action/approval/notification/condition), JSONB steps
- Workflow lifecycle: pending → in_progress → completed/rejected/cancelled
- Event-triggered workflows: event bus → auto-start instances
- Code-engine workflows: onboarding on user.created event
- Approval timeout: auto-reject after configured hours
- 5 new tenant-scoped tables with RLS: ai_conversations, ai_messages, workflows, workflow_instances, workflow_step_history
- Migration 0004: all tables + RLS policies + tenant_id + indexes
- 238 tests pass (30 AC + 105 coverage + 103 existing), 84.12% T09 module coverage
- MissingGreenlet fix: safe accessor helpers for async ORM attribute access

app/schemas/ai_copilot.py

@@ -0,0 +1,62 @@
+"""AI Copilot schemas — query, execute, history."""
+
+from __future__ import annotations
+
+from pydantic import BaseModel, Field
+
+
+class CopilotQueryRequest(BaseModel):
+    """Natural language query to the AI copilot."""
+    query: str = Field(..., min_length=1, max_length=2000)
+    conversation_id: str | None = None
+    context: dict = Field(default_factory=dict)
+
+
+class CopilotAction(BaseModel):
+    """A proposed API action derived from NL input."""
+    method: str = Field(..., pattern="^(GET|POST|PATCH|DELETE)$")
+    path: str = Field(..., min_length=1)
+    body: dict | None = None
+    description: str = ""
+    confidence: float = Field(0.0, ge=0.0, le=1.0)
+
+
+class CopilotQueryResponse(BaseModel):
+    """Response from copilot query — proposed actions for user confirmation."""
+    conversation_id: str
+    message: str
+    proposed_actions: list[CopilotAction] = Field(default_factory=list)
+
+
+class CopilotExecuteRequest(BaseModel):
+    """Execute a proposed action after user confirmation."""
+    conversation_id: str
+    action: CopilotAction
+
+
+class CopilotExecuteResponse(BaseModel):
+    """Result of executing a proposed action."""
+    conversation_id: str
+    success: bool
+    status_code: int
+    data: dict | list | None = None
+    error: str | None = None
+
+
+class CopilotMessageResponse(BaseModel):
+    """A single message in conversation history."""
+    id: str
+    role: str
+    content: str
+    proposed_actions: list[dict] | None = None
+    executed_action: dict | None = None
+    execution_result: dict | None = None
+    created_at: str | None = None
+
+
+class CopilotHistoryResponse(BaseModel):
+    """Paginated conversation history."""
+    items: list[CopilotMessageResponse]
+    total: int
+    page: int
+    page_size: int