fix: restore legacy blur strength + re-enable embed fetch error logging

Scale two-pass Gaussian blur strength by 1/3 to match the old single-pass
behavior — blur(5) was producing ~3x stronger output after the rewrite,
breaking pieces like $4bb that rely on specific blur levels.

Re-enable console.warn for network errors in fetchCachedCode so embed
failures are visible in devtools instead of silently swallowed.

Co-Authored-By: Claude Opus 4.6 (1M context) <[e-mail]>

system/public/aesthetic.computer/lib/graph.mjs

···
 // Creates smooth blur effect by applying horizontal then vertical Gaussian convolution
 function blur(strength = 1, quality = "medium") {
   if (strength <= 0.1) return; // No blur needed - neutral blur
-  
+
   // Start timing for performance monitoring
   const blurStartTime = performance.now();
-  
+
+  // Scale strength to match legacy single-pass blur behavior.
+  // The two-pass separable Gaussian is ~3x stronger than the old
+  // single-pass weighted blur at the same radius value.
+  const scaledStrength = strength / 3;
+
   // Accumulate the blur strength for progressive blurring
-  blurAccumulator += strength;
+  blurAccumulator += scaledStrength;
   
   // Apply blur when accumulator reaches threshold
   const threshold = 0.5;

system/public/aesthetic.computer/lib/kidlisp.mjs

···
             resolve(null);
           }
         }).catch(error => {
+          console.warn(`⚠️ Network error loading embedded piece $${nanoidCode}:`, error.message || error);
           resolve(null);
         });
       }