feat(insta-lab): internal webhook /api/internal/insta/update (SP-4)

Windows insta-render worker가 작업 진행률·완료·실패를 보고할 수신부.
X-Internal-Key 인증 필수. 4건의 단위 테스트로 status·error·result_path 검증.

Plan-B-Insta Phase 1.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

insta-lab/app/internal_router.py

@@ -0,0 +1,63 @@
+"""SP-4 — Windows insta-render → NAS internal webhook.
+
+POST /api/internal/insta/update
+- X-Internal-Key 인증 필수
+- task DB row update (status, progress, result_path, error)
+- result_path는 nginx 서빙 경로 (예: /media/insta/{slate_id}/01.png)
+- succeeded 시 params에서 slate_id 추출 → result_id 세팅
+"""
+from __future__ import annotations
+
+import json
+import logging
+from typing import Optional
+
+from fastapi import APIRouter, Depends, HTTPException
+from pydantic import BaseModel, Field
+
+from . import db
+from .auth import verify_internal_key
+
+logger = logging.getLogger(__name__)
+router = APIRouter()
+
+
+class UpdatePayload(BaseModel):
+    task_id: str
+    status: str = Field(..., description="processing|succeeded|failed")
+    progress: int = Field(..., ge=0, le=100)
+    result_path: Optional[str] = None
+    error: Optional[str] = None
+
+
+@router.post(
+    "/api/internal/insta/update",
+    dependencies=[Depends(verify_internal_key)],
+)
+def insta_update(payload: UpdatePayload):
+    task = db.get_task(payload.task_id)
+    if task is None:
+        raise HTTPException(404, f"task not found: {payload.task_id}")
+
+    result_id = None
+    if payload.status == "succeeded":
+        try:
+            # DB stores params (not input_data) from create_task
+            params_data = json.loads(task.get("params") or "{}")
+            result_id = params_data.get("slate_id")
+        except (ValueError, TypeError):
+            pass
+
+    db.update_task(
+        payload.task_id,
+        payload.status,
+        payload.progress,
+        message=payload.result_path or "",
+        result_id=result_id,
+        error=payload.error,
+    )
+    logger.info(
+        "internal/insta/update task=%s status=%s progress=%d",
+        payload.task_id, payload.status, payload.progress,
+    )
+    return {"ok": True}