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-dimmer.yaml

@@ -35,7 +35,7 @@ esp32:
   framework:
     type: esp-idf
 
-  
+
 packages:
   common: !include common/common.yaml