Add startup environment diagnostics (_log_env)

Prints GPU name/VRAM/compute cap, CUDA version, cuDNN version, system
RAM, and key library versions (spaces, diffusers, transformers, gradio,
accelerate, peft, torchvision) at startup. Exceptions always print the
error message — no silent pass. This would have instantly identified
spaces==0.51.0 as the culprit during the July 17 outage.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -34,6 +34,33 @@ print("torch.__version__ =", torch.__version__, flush=True)
 print("Using device:", device, flush=True)
 print(f"CUDA device_count={torch.cuda.device_count()}, is_available={torch.cuda.is_available()}", flush=True)
 
+
+def _log_env():
+    import importlib.metadata as _meta
+    if torch.cuda.is_available():
+        p = torch.cuda.get_device_properties(0)
+        print(f"[env] GPU: {p.name}, VRAM={p.total_memory/1024**3:.1f}GB, cap={p.major}.{p.minor}", flush=True)
+    print(f"[env] CUDA (torch build): {torch.version.cuda}", flush=True)
+    print(f"[env] cuDNN: {torch.backends.cudnn.version()}", flush=True)
+    for pkg in ["spaces", "diffusers", "transformers", "gradio", "accelerate", "peft", "torchvision"]:
+        try:
+            print(f"[env] {pkg}=={_meta.version(pkg)}", flush=True)
+        except Exception as e:
+            print(f"[env] {pkg}==? ({e})", flush=True)
+    try:
+        mem = {}
+        with open("/proc/meminfo") as f:
+            for line in f:
+                k, v = line.split(":", 1)
+                mem[k.strip()] = v.strip()
+        total_gb = int(mem["MemTotal"].split()[0]) / 1024**2
+        avail_gb = int(mem["MemAvailable"].split()[0]) / 1024**2
+        print(f"[env] RAM: {total_gb:.0f}GB total, {avail_gb:.0f}GB available", flush=True)
+    except Exception as e:
+        print(f"[env] RAM: unavailable ({e})", flush=True)
+
+_log_env()
+
 # TF32 matmul: ~10-15% free speedup on Ampere/Hopper (bfloat16 accumulation paths benefit too)
 torch.backends.cuda.matmul.allow_tf32 = True
 torch.backends.cudnn.allow_tf32 = True