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/render/plugins/inplace-pdf-viewer.ts

@@ -4,9 +4,7 @@ export function newInplacePluginPdfViewer(): InplaceRenderPlugin {
   return {
     name: 'pdf-viewer',
 
-    canHandle(filename: string, _mimeType: string): boolean {
-      return filename.toLowerCase().endsWith('.pdf');
-    },
+    canHandle: (filename: string, _mimeType: string): boolean => filename.toLowerCase().endsWith('.pdf'),
 
     async render(container: HTMLElement, fileUrl: string): Promise<void> {
       const PDFObject = await import('pdfobject');