Temporarily widen the busy-wait ceiling to diagnose a hang on real hardware

First hardware run: busy never cleared within the 16s ceiling (timed out
at almost exactly that value), and the engine proceeded to declare the
update done anyway, leaving the panel mid-waveform (solid black). Bumping
to 60s to find out whether the panel just needs longer than expected or
whether busy genuinely never clears at all - the two point at very
different next steps.

components/gxepd2/panel_213_z98c.h

@@ -51,7 +51,7 @@ inline const EpdPanelDescriptor PANEL_213_Z98C = {
     .width = 128,   // RAM window width - _setPartialRamArea works in this, not WIDTH_VISIBLE (122)
     .height = 250,
     .busy_active_level = true,  // GxEPD2_EPD(..., /*busy_level=*/HIGH, ...)
-    .busy_timeout_ms = 16000,
+    .busy_timeout_ms = 60000,  // temporarily generous - diagnosing a busy-never-clears hang, see commit message
     .init_sequence = PANEL_213_Z98C_INIT,
     .init_sequence_len = sizeof(PANEL_213_Z98C_INIT) / sizeof(PANEL_213_Z98C_INIT[0]),
     .plane_count = 2,