fix(log): raise web log line cap to 256 to match the capture buffer

The vprintf trampoline already captures into a 256-byte buffer, but push_line
re-truncated to max_line_length=128, clipping any log line past 128 chars in
the web log viewer (only visible once the viewer started parsing again). Raise
the default to 256 so the buffered copy keeps what was already captured; the
2-second age window bounds retained volume, so the added worst-case RAM is
small. Lines longer than the 256-byte capture buffer still clip.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: mairas

src/sensesp/system/log_buffer.h

@@ -59,7 +59,7 @@ struct LogSnapshot {
 class LogBuffer {
  public:
   explicit LogBuffer(size_t max_lines = 200, uint32_t max_age_ms = 2000,
-                     size_t max_line_length = 128);
+                     size_t max_line_length = 256);
 
   /**
    * @brief Install the chained vprintf hook. Call once, early in startup.