Add ESLint, pre-commit hook & format all files (#319)

* Add ESLint config

* Add ESLint packages

* Add prettier config

* Fix ESLint package version

* Format all files

* Format static assets

* Format project root config

* Add pre-commit code formatting

Formats .css & .js files automatically.  If any .ts or .mts files are staged, the entire project is type-checked.

Packages:
- lint-staged
- husky
- prettier

.prettierrc

@@ -1,5 +1,8 @@
 {
-    "singleQuote": false,
-    "semi": true,
-    "tabWidth": 2
+  "singleQuote": false,
+  "semi": false,
+  "tabWidth": 2,
+  "trailingComma": "all",
+  "overrides": [{ "files": "*.ts", "options": { "requirePragma": true } }],
+  "arrowParens": "avoid"
 }