feat: Graphify build worker endpoints + UI trigger

- POST /api/aos/instances/[id]/graph-build: trigger or get build command
- POST /api/aos/instances/[id]/graph-status: worker callback (ok/error)
- GET /api/aos/graphify-health: check if Graphify service is up
- Instance detail: 'Graph neu erstellen' button (visible when demo_active/active)
- Graceful degradation: if GRAPHIFY_URL not set, returns build command for external worker

src/app/api/aos/instances/[id]/graph-status/route.ts

@@ -0,0 +1,75 @@
+import { NextResponse } from 'next/server'
+import { db } from '@/lib/db'
+
+export const dynamic = 'force-dynamic'
+
+// POST /api/aos/instances/[id]/graph-status
+// Called by the graph build worker after it finishes (success or failure).
+// Body: { status: 'ok' | 'error', stats?: {...}, error?: '...' }
+//
+// This is the callback endpoint that completes the graph build lifecycle:
+//   1. AOS queues build (graphify.build.queued)
+//   2. Worker picks up, calls POST /graph-build, gets the command
+//   3. Worker executes graphify CLI
+//   4. Worker calls this endpoint to report success/failure
+//   5. AOS records graphify.build.ok / graphify.build.error
+export async function POST(req: Request, { params }: { params: Promise<{ id: string }> }) {
+  try {
+    const { id } = await params
+    const body = await req.json().catch(() => ({}))
+    const status = body.status === 'ok' ? 'ok' : 'error'
+
+    const instance = await db.instance.findUnique({ where: { id } })
+    if (!instance) {
+      return NextResponse.json({ error: 'instance not found' }, { status: 404 })
+    }
+
+    if (status === 'ok') {
+      await db.instanceEvent.create({
+        data: {
+          instanceId: id,
+          type: 'graphify.build.ok',
+          step: 'graphify',
+          result: 'ok',
+          details: JSON.stringify({
+            stats: body.stats ?? null,
+            graphPath: body.graphPath ?? null,
+            builtAt: new Date().toISOString(),
+          }),
+        },
+      })
+      await db.auditLog.create({
+        data: {
+          actor: 'graphify-worker',
+          action: 'graphify.build.ok',
+          entity: 'Instance',
+          entityId: id,
+          after: JSON.stringify({ stats: body.stats }),
+          hash: 'sha256:' + Math.random().toString(36).slice(2),
+        },
+      })
+      return NextResponse.json({ ok: true, status: 'ok' })
+    } else {
+      await db.instanceEvent.create({
+        data: {
+          instanceId: id,
+          type: 'graphify.build.error',
+          step: 'graphify',
+          result: 'error',
+          details: JSON.stringify({ error: body.error ?? 'unknown build error' }),
+        },
+      })
+      await db.instance.update({
+        where: { id },
+        data: {
+          lastError: `graphify build failed: ${body.error ?? 'unknown'}`,
+          lastErrorAt: new Date(),
+        },
+      })
+      return NextResponse.json({ ok: false, status: 'error', error: body.error })
+    }
+  } catch (err) {
+    const msg = err instanceof Error ? err.message : 'internal server error'
+    return NextResponse.json({ error: msg }, { status: 500 })
+  }
+}