Improve runtime stutter handling and ground clutter performance

- reduce per-tile ground clutter generation pressure and enforce tighter caps to avoid spikes

- remove expensive detail dedupe scans from the hot render path

- add progressive/lazy clutter updates around player movement to smooth frame pacing

- lower noisy runtime INFO logging to DEBUG/throttled paths

- keep terrain/game screen updates responsive while preserving existing behavior

src/pipeline/m2_loader.cpp

@@ -368,12 +368,15 @@ std::string readString(const std::vector<uint8_t>& data, uint32_t offset, uint32
         return "";
     }
 
-    // Strip trailing null bytes (M2 nameLength includes \0)
-    while (length > 0 && data[offset + length - 1] == 0) {
-        length--;
+    // M2 string blocks are C-strings. Some extracted files have a valid
+    // string terminated early with embedded NUL and garbage bytes after it.
+    // Respect first NUL within the declared length.
+    uint32_t actualLen = 0;
+    while (actualLen < length && data[offset + actualLen] != 0) {
+        actualLen++;
     }
 
-    return std::string(reinterpret_cast<const char*>(&data[offset]), length);
+    return std::string(reinterpret_cast<const char*>(&data[offset]), actualLen);
 }
 
 enum class TrackType { VEC3, QUAT_COMPRESSED, FLOAT };