Fix trailing spaces and missing newlines in all mcu-*.yaml files

Bulk cleanup: remove trailing whitespace and ensure files end with a
newline. Structural issues (indentation, bracket spacing) left for
per-file fixes.

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

mcu-lightening.yaml

@@ -10,7 +10,7 @@ esphome:
   friendly_name: ${name}
   area: ${area}
   comment: ${comment}
-  
+
 esp32:
   variant: esp32
   framework: