chore: upgrade eslint plugins, remove eslint-plugin-github (#38046)

- Bump `eslint`, `typescript-eslint` and `eslint-plugin-unicorn` (to
v68), and configure the rules added in unicorn v66/v67/v68.
- Remove `eslint-plugin-github` and its workarounds (rules, type stub,
pnpm peer override, in-code `eslint-disable` comments); the rules worth
keeping are covered by `unicorn` equivalents.
- Apply the resulting fixes and autofixes across the JS codebase.

_Prepared with Claude (Opus 4.8)._

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/modules/toast.ts

@@ -45,7 +45,7 @@ type ToastifyElement = HTMLElement & {_giteaToastifyInstance?: Toast};
 /** See https://github.com/apvarun/toastify-js#api for options */
 function showToast(message: string, level: Intent, {gravity, position, duration, useHtmlBody, preventDuplicates = true, ...other}: ToastOpts = {}): Toast | null {
   const parent = document.querySelector('.ui.dimmer.active') ?? document.body;
-  const duplicateKey = preventDuplicates ? (preventDuplicates === true ? `${level}-${message}` : preventDuplicates) : '';
+  const duplicateKey = preventDuplicates ? (typeof preventDuplicates === 'string' ? preventDuplicates : `${level}-${message}`) : '';
 
   // prevent showing duplicate toasts with the same level and message, and give visual feedback for end users
   if (preventDuplicates) {