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-office-r.yaml

@@ -3,7 +3,7 @@ substitutions:
   name: Office R
   area: Office R
   comment: "${area} | MS Teams presence"
-  
+
 esphome:
   name: mcu-${device}
   friendly_name: ${name}
@@ -54,4 +54,4 @@ output:
     pin: 5
   - platform: ledc
     id: led_blue
-    pin: 6
+    pin: 6