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>

eslint.config.js

@@ -0,0 +1,31 @@
+import js from '@eslint/js'
+import pluginVue from 'eslint-plugin-vue'
+import eslintConfigPrettier from 'eslint-config-prettier'
+import globals from 'globals'
+
+export default [
+    {
+        ignores: ['dist/**', 'node_modules/**']
+    },
+    js.configs.recommended,
+    ...pluginVue.configs['flat/recommended'],
+    eslintConfigPrettier,
+    {
+        languageOptions: {
+            ecmaVersion: 'latest',
+            sourceType: 'module',
+            globals: {
+                ...globals.browser,
+                ...globals.node
+            }
+        },
+        rules: {
+            'vue/multi-word-component-names': 'off',
+            'vue/require-default-prop': 'off',
+            'vue/attributes-order': 'off',
+            'vue/first-attribute-linebreak': 'off',
+            'no-unused-vars': ['warn', { argsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' }],
+            'no-console': 'off'
+        }
+    }
+]