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/workflow.py

@@ -0,0 +1,105 @@
+"""Workflow schemas — create, update, read, instance lifecycle, step history."""
+
+from __future__ import annotations
+
+from pydantic import BaseModel, Field
+
+
+class WorkflowStep(BaseModel):
+    """A single step in a workflow definition."""
+    name: str = Field(..., min_length=1, max_length=200)
+    type: str = Field(..., pattern="^(action|approval|notification|condition)$")
+    config: dict = Field(default_factory=dict)
+    description: str | None = None
+
+
+class WorkflowCreate(BaseModel):
+    """Create a new workflow definition."""
+    name: str = Field(..., min_length=1, max_length=200)
+    description: str | None = None
+    trigger_event: str | None = None
+    steps: list[WorkflowStep] = Field(..., min_length=1)
+    is_active: bool = True
+
+
+class WorkflowUpdate(BaseModel):
+    """Update an existing workflow definition."""
+    name: str | None = Field(None, max_length=200)
+    description: str | None = None
+    trigger_event: str | None = None
+    steps: list[WorkflowStep] | None = None
+    is_active: bool | None = None
+
+
+class WorkflowResponse(BaseModel):
+    """Workflow definition response."""
+    id: str
+    name: str
+    description: str | None = None
+    trigger_event: str | None = None
+    steps: list[dict]
+    is_active: bool
+    created_by: str | None = None
+    created_at: str | None = None
+    updated_at: str | None = None
+
+
+class WorkflowListResponse(BaseModel):
+    """Paginated workflow list."""
+    items: list[WorkflowResponse]
+    total: int
+    page: int
+    page_size: int
+
+
+class InstanceCreate(BaseModel):
+    """Create a new workflow instance."""
+    context: dict = Field(default_factory=dict)
+    timeout_hours: int | None = None
+
+
+class InstanceResponse(BaseModel):
+    """Workflow instance response with current state and history."""
+    id: str
+    workflow_id: str
+    status: str
+    current_step_index: int
+    context: dict
+    initiated_by: str | None = None
+    completed_at: str | None = None
+    timeout_hours: int | None = None
+    timeout_at: str | None = None
+    created_at: str | None = None
+    updated_at: str | None = None
+
+
+class InstanceDetailResponse(InstanceResponse):
+    """Instance with step history."""
+    history: list[dict] = Field(default_factory=list)
+    workflow_name: str | None = None
+
+
+class InstanceListResponse(BaseModel):
+    """Paginated instance list."""
+    items: list[InstanceResponse]
+    total: int
+    page: int
+    page_size: int
+
+
+class AdvanceRequest(BaseModel):
+    """Advance or reject a workflow instance step."""
+    decision: str = Field(..., pattern="^(approve|reject)$")
+    comment: str | None = None
+
+
+class StepHistoryResponse(BaseModel):
+    """Step history entry."""
+    id: str
+    instance_id: str
+    step_index: int
+    step_type: str
+    action: str
+    actor_id: str | None = None
+    details: dict | None = None
+    created_at: str | None = None