feat: add LOG_LEVEL env var and improve error messages

Add configurable LOG_LEVEL (fatal/error/warn/info/debug/trace) for
Fastify logger. Always return error details in tool processing
responses and combine error + details in frontend display.

apps/api/src/index.ts

@@ -34,7 +34,7 @@ await ensureDefaultAdmin();
 recoverStaleJobs();
 
 const app = Fastify({
-  logger: true,
+  logger: { level: env.LOG_LEVEL },
   bodyLimit: env.MAX_UPLOAD_SIZE_MB * 1024 * 1024,
 });
 

apps/api/src/lib/env.ts

@@ -28,6 +28,7 @@ const envSchema = z.object({
   APP_NAME: z.string().default("Stirling Image"),
   CORS_ORIGIN: z.string().default(""),
   MAX_USERS: z.coerce.number().default(5),
+  LOG_LEVEL: z.enum(["fatal", "error", "warn", "info", "debug", "trace"]).default("info"),
 });
 
 export type Env = z.infer<typeof envSchema>;

apps/api/src/routes/tool-factory.ts

@@ -306,7 +306,7 @@ export function createToolRoute<T>(app: FastifyInstance, config: ToolRouteConfig
         request.log.error({ err, toolId: config.toolId }, "Tool processing failed");
         return reply.status(422).send({
           error: "Processing failed",
-          details: process.env.NODE_ENV === "production" ? undefined : message,
+          details: message,
         });
       }
     },

apps/web/src/hooks/use-tool-processor.ts

@@ -186,7 +186,10 @@ export function useToolProcessor(toolId: string) {
         } else {
           try {
             const body = JSON.parse(xhr.responseText);
-            setError(body.error || body.details || `Processing failed: ${xhr.status}`);
+            const msg = body.details
+              ? `${body.error}: ${body.details}`
+              : body.error || `Processing failed: ${xhr.status}`;
+            setError(msg);
           } catch {
             setError(`Processing failed: ${xhr.status}`);
           }
@@ -305,7 +308,9 @@ export function useToolProcessor(toolId: string) {
           let errorMsg: string;
           try {
             const body = JSON.parse(text);
-            errorMsg = body.error || body.details || `Batch processing failed: ${response.status}`;
+            errorMsg = body.details
+              ? `${body.error}: ${body.details}`
+              : body.error || `Batch processing failed: ${response.status}`;
           } catch {
             errorMsg = `Batch processing failed: ${response.status}`;
           }

docker/Dockerfile

@@ -182,7 +182,8 @@ ENV PORT=1349 \
     MAX_BATCH_SIZE=200 \
     CONCURRENT_JOBS=3 \
     MAX_MEGAPIXELS=100 \
-    RATE_LIMIT_PER_MIN=100
+    RATE_LIMIT_PER_MIN=100 \
+    LOG_LEVEL=info
 
 # NVIDIA Container Toolkit env vars (harmless on non-GPU systems)
 ENV NVIDIA_VISIBLE_DEVICES=all \