feat(health): include degraded reasons in responses

ts/ui/server.ts

@@ -151,6 +151,7 @@ export class UiServer {
     const gpus = await this.gpuDetector.detectGpus();
 
     let status: 'ok' | 'degraded' | 'error' = 'ok';
+    const reasons = new Set<'unhealthy_container' | 'no_models_available' | 'gpu_detection_failed'>();
     const containerHealth: Record<string, 'healthy' | 'unhealthy'> = {};
     const gpuStatus: Record<string, 'available' | 'in_use' | 'error'> = {};
 
@@ -160,14 +161,21 @@ export class UiServer {
       } else {
         containerHealth[id] = 'unhealthy';
         status = 'degraded';
+        reasons.add('unhealthy_container');
       }
     }
     for (const gpu of gpus) {
       gpuStatus[gpu.id] = 'available';
     }
 
+    if (models.size === 0) {
+      status = 'degraded';
+      reasons.add('no_models_available');
+    }
+
     const health: IHealthResponse = {
       status,
+      reasons: Array.from(reasons),
       version: VERSION,
       uptime: Math.floor((Date.now() - this.startTime) / 1000),
       containers: statuses.size,