Fix: markdownlint MD012/MD019 errors in build-pattern-conversion-plan.md

- Removed extra blank lines at end of file to resolve MD012 (no-multiple-blanks)
- Standardized heading spacing to resolve MD019 (no-multiple-space-atx)
- Stripped trailing whitespace and ensured file ends with a single newline

All changes maintain content integrity and bring the file into full markdownlint compliance.

src/main.common.ts

@@ -10,8 +10,6 @@ import { FontAwesomeIcon } from "./libs/fontawesome";
 import Camera from "simple-vue-camera";
 import { logger } from "./utils/logger";
 
-// const platform = process.env.VITE_PLATFORM;
-// const pwa_enabled = process.env.VITE_PWA_ENABLED === "true";
 
 // Global Error Handler
 function setupGlobalErrorHandler(app: VueApp) {