fix(ci): remove JSON insert_final_newline override in .editorconfig

JSON files already have final newlines, so they should inherit the
default insert_final_newline=true from [*] instead of overriding to
false (which was originally "ignore", an invalid value).

https://claude.ai/code/session_01UNAUtVFRfFTyfXXLy7dJNz

Author: claude

.editorconfig

@@ -9,9 +9,6 @@ charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
 
-[*.json]
-insert_final_newline = false
-
 [Makefile]
 indent_style = tab