AUTO-001: add automation approval workflow

Closes #21

app/api/v1/automations.py

@@ -0,0 +1,77 @@
+from __future__ import annotations
+
+from fastapi import APIRouter, HTTPException, Request, Response, status
+
+from app.automations.models import (
+    AutomationProposal,
+    ProposalDecision,
+    ProposalStatus,
+)
+from app.automations.store import AutomationStore
+
+router = APIRouter(prefix="/v1/automations", tags=["automations"])
+
+
+@router.post("/proposals", response_model=AutomationProposal, status_code=201)
+def create_proposal(payload: AutomationProposal, request: Request) -> AutomationProposal:
+    if payload.trigger.above is None and payload.trigger.below is None:
+        raise HTTPException(status_code=422, detail="Trigger benötigt above oder below.")
+    return _store(request).create(payload.model_copy(update={"status": ProposalStatus.DRAFT}))
+
+
+@router.get("/proposals", response_model=list[AutomationProposal])
+def list_proposals(request: Request) -> list[AutomationProposal]:
+    return _store(request).list()
+
+
+@router.post("/proposals/{proposal_id}/approve", response_model=AutomationProposal)
+def approve(
+    proposal_id: str,
+    payload: ProposalDecision,
+    request: Request,
+) -> AutomationProposal:
+    return _decide(request, proposal_id, ProposalStatus.APPROVED, payload.expected_revision)
+
+
+@router.post("/proposals/{proposal_id}/reject", response_model=AutomationProposal)
+def reject(
+    proposal_id: str,
+    payload: ProposalDecision,
+    request: Request,
+) -> AutomationProposal:
+    return _decide(request, proposal_id, ProposalStatus.REJECTED, payload.expected_revision)
+
+
+@router.get("/proposals/{proposal_id}/yaml")
+def export_yaml(proposal_id: str, request: Request) -> Response:
+    try:
+        content = _store(request).export_yaml(proposal_id)
+    except KeyError as exc:
+        raise HTTPException(status_code=404, detail=str(exc)) from exc
+    except ValueError as exc:
+        raise HTTPException(status_code=409, detail=str(exc)) from exc
+    return Response(content=content, media_type="application/yaml")
+
+
+def _decide(
+    request: Request,
+    proposal_id: str,
+    decision: ProposalStatus,
+    expected_revision: int,
+) -> AutomationProposal:
+    try:
+        return _store(request).decide(proposal_id, decision, expected_revision)
+    except KeyError as exc:
+        raise HTTPException(status_code=404, detail=str(exc)) from exc
+    except ValueError as exc:
+        raise HTTPException(status_code=409, detail=str(exc)) from exc
+
+
+def _store(request: Request) -> AutomationStore:
+    store = getattr(request.app.state, "automation_store", None)
+    if not isinstance(store, AutomationStore):
+        raise HTTPException(
+            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+            detail="Automation Store nicht initialisiert.",
+        )
+    return store