refactor: harden deps, fix geo math, and add engineering tooling

Replace xlsx with exceljs, unify CRS/DMS logic, move pages to views with shared map/toast composables, and add Vitest/ESLint/Prettier plus docs.

Co-authored-by: Cursor <cursoragent@cursor.com>

vitest.config.js

@@ -0,0 +1,10 @@
+import { defineConfig } from 'vite'
+import vue from '@vitejs/plugin-vue'
+
+export default defineConfig({
+    plugins: [vue()],
+    test: {
+        environment: 'node',
+        include: ['src/**/*.{test,spec}.{js,mjs}']
+    }
+})