fix: replace Browserify with Webpack to resolve security vulnerabilities (#399)

* fix: replace Browserify with Webpack to resolve security vulnerabilities

* fix: add clean script and update start scripts

- Add 'clean' script to remove stale bundle.raw.js artifact
- Update 'build' script to run clean before replace and compile
- Replace deprecated budo/bistre with webpack-dev-server for development
- Add webpack-dev-server to devDependencies
- Simplify start-prod to just run build
- Configure webpack-dev-server to serve static files from project root

Prevents stale Browserify output from being confused with active build artifacts.
Addresses reviewer feedback on PR #399

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Migrate ESLint to v9+ flat config format

- Replace .eslintrc (deprecated) with eslint.config.js
- Move ignore patterns from .eslintignore to ignores property
- Update languageOptions with proper globals for Node and browser
- Add type: module to package.json to eliminate Node warnings

This resolves ESLint v10.2.0 compatibility issues.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Remove unused no-eq-null eslint-disable directive

The directive on line 2 was unused since the actual comparisons
with null already have their own disable comments on lines 6 and 14.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Remove type: module from package.json

Adding type: module breaks CommonJS scripts used in the build process.
ESLint can handle eslint.config.js as ESM without the type field.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Rename eslint.config.js to eslint.config.mjs

Using .mjs extension explicitly marks the file as an ES module,
eliminating the MODULE_TYPELESS_PACKAGE_JSON warning without
requiring type: module in package.json (which breaks build scripts).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: rahulkumaar03 <techieeboy04@gmail.com>
Co-authored-by: Dennis Luxen <ich@dennisluxen.de>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 4 people

.eslintignore

@@ -0,0 +1,13 @@
+/* @preserve
+ * Leaflet 1.9.4, a JS library for interactive maps. https://leafletjs.com
+ * (c) 2010-2023 Vladimir Agafonkin, (c) 2010-2011 CloudMade
+ */
+
+/* @preserve
+ * Leaflet Control Geocoder
+ * https://github.com/perliedman/leaflet-control-geocoder
+ *
+ * Copyright (c) 2012 sa3m (https://github.com/sa3m)
+ * Copyright (c) 2018 Per Liedman
+ * All rights reserved.
+ */

.eslintrc

@@ -0,0 +1,53 @@
+import js from '@eslint/js';
+
+export default [
+  {
+    ignores: ['node_modules/**', 'bundle*.js', 'dist/**', 'debug/**']
+  },
+  {
+    files: ['src/**/*.js', 'i18n/**/*.js'],
+    languageOptions: {
+      ecmaVersion: 2021,
+      sourceType: 'module',
+      globals: {
+        L: 'readonly',
+        // Node globals
+        global: 'readonly',
+        process: 'readonly',
+        Buffer: 'readonly',
+        __dirname: 'readonly',
+        __filename: 'readonly',
+        // Browser globals
+        window: 'readonly',
+        document: 'readonly',
+        navigator: 'readonly',
+        console: 'readonly'
+      }
+    },
+    rules: {
+      indent: [2, 2],
+      'comma-dangle': [2, 'never'],
+      'space-before-blocks': 2,
+      'keyword-spacing': 2,
+      'space-unary-ops': 2,
+      'no-use-before-define': [2, 'nofunc'],
+      camelcase: 0,
+      'comma-style': 2,
+      eqeqeq: 0,
+      'new-cap': 2,
+      'no-new': 2,
+      'brace-style': 2,
+      'no-multi-spaces': 0,
+      'no-underscore-dangle': 0,
+      'no-self-compare': 2,
+      'no-void': 2,
+      'no-eq-null': 2,
+      quotes: 0,
+      curly: 0,
+      'dot-notation': 0,
+      'no-shadow': 0,
+      'no-alert': 0,
+      'consistent-return': 0
+    }
+  }
+];