web: update to ESLint 9 (#10812)

* web: update to ESLint 9

ESLint 9 has been out for awhile now, and all of the plug-ins that we use have caught up, so it is
time to bite the bullet and upgrade.  This commit:

- upgrades to ESLint 9, and upgrades all associated plugins
- Replaces the `.eslintrc` and `.eslintignore` files with the new, "flat" configuration file,
  "eslint.config.mjs".
- Places the previous "precommit" and "nightmare" rules in `./scripts/eslint.precommit.mjs` and
  `./scripts/eslint.nightmare.mjs`, respectively
- Replaces the scripted wrappers for eslint (`eslint`, `eslint-precommit`) with a single executable
  that takes the arguments `--precommit`, which applies a stricter set of rules, and `--nightmare`,
  which applies an even more terrifyingly strict set of rules.
- Provides the scripted wrapper `./scripts/eslint.mjs` so that eslint can be run from `bun`, if one
  so chooses.
- Fixes *all* of the lint `eslint.config.mjs` now finds, including removing all of the `eslint`
  styling rules and overrides because Eslint now proudly leaves that entirely up to Prettier.

To shut Dependabot up about ESLint.

* Added explanation for no-console removal.

* web: did not need the old and unmaintained nightmare mode; it can be configured directly.

web/src/locale-codes.ts

@@ -4,44 +4,44 @@
 /**
  * The locale code that templates in this source code are written in.
  */
-export const sourceLocale = `en`;
+export const sourceLocale = "en";
 
 /**
  * The other locale codes that this application is localized into. Sorted
  * lexicographically.
  */
 export const targetLocales = [
-  `de`,
-  `en`,
-  `es`,
-  `fr`,
-  `ko`,
-  `nl`,
-  `pl`,
-  `pseudo-LOCALE`,
-  `tr`,
-  `zh_TW`,
-  `zh-CN`,
-  `zh-Hans`,
-  `zh-Hant`,
+  "de",
+  "en",
+  "es",
+  "fr",
+  "ko",
+  "nl",
+  "pl",
+  "pseudo-LOCALE",
+  "tr",
+  "zh_TW",
+  "zh-CN",
+  "zh-Hans",
+  "zh-Hant",
 ] as const;
 
 /**
  * All valid project locale codes. Sorted lexicographically.
  */
 export const allLocales = [
-  `de`,
-  `en`,
-  `en`,
-  `es`,
-  `fr`,
-  `ko`,
-  `nl`,
-  `pl`,
-  `pseudo-LOCALE`,
-  `tr`,
-  `zh_TW`,
-  `zh-CN`,
-  `zh-Hans`,
-  `zh-Hant`,
+  "de",
+  "en",
+  "en",
+  "es",
+  "fr",
+  "ko",
+  "nl",
+  "pl",
+  "pseudo-LOCALE",
+  "tr",
+  "zh_TW",
+  "zh-CN",
+  "zh-Hans",
+  "zh-Hant",
 ] as const;