Upgrade ESLint to v9 with flat config (#9680)

* Upgrade ESLint to v9 with flat config

- Upgrade eslint from v8 to v9.18.0
- Migrate from .eslintrc.js to eslint.config.mjs (flat config)
- Upgrade typescript-eslint to v8.20.0 (unified package)
- Replace eslint-plugin-import with eslint-plugin-import-x for flat config support
- Add globals package for environment globals
- Update eslint-plugin-bsky-internal with proper meta objects for ESLint v9
- Fix deprecated context.getScope() API usage
- Update bskyembed to use flat config
- Remove deprecated --ext flag from lint scripts
- Configure rules to maintain previous behavior while using new ESLint version

* Fix varsIgnorePattern to require character after underscore

Restore the original pattern `^_.+` instead of `^_` so that lingui's
`const { _ } = useLingui()` will still be flagged when unused.

* Update ESLint rule tests for flat config format

- Update RuleTester to use flat config languageOptions instead of
  eslintrc parser format
- Remove duplicate test case that ESLint v9 now detects
- Add Jest globals for test files

* update eslint package versions

* lint android a11y

* enable typechecked rules, switch them to warn

* fix yarn lock ci

* Fix CI failure

* Remove unused globals?

* Organize a bit, add quiet to main lint command

* Allow ternary

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Eric Bailey <git@esb.lol>

src/components/live/EditLiveDialog.tsx

@@ -98,7 +98,7 @@ function DialogInner({
   } = useRemoveLiveStatusMutation()
 
   const {minutesUntilExpiry, expiryDateTime} = useMemo(() => {
-    tick!
+    void tick
 
     const expiry = new Date(status.expiresAt ?? new Date())
     return {

src/components/live/GoLiveDialog.tsx

@@ -13,7 +13,11 @@ import {Admonition} from '#/components/Admonition'
 import {Button, ButtonIcon, ButtonText} from '#/components/Button'
 import * as Dialog from '#/components/Dialog'
 import * as TextField from '#/components/forms/TextField'
-import {getLiveServiceNames} from '#/components/live/utils'
+import {
+  displayDuration,
+  getLiveServiceNames,
+  useDebouncedValue,
+} from '#/components/live/utils'
 import {Loader} from '#/components/Loader'
 import * as ProfileCard from '#/components/ProfileCard'
 import * as Select from '#/components/Select'
@@ -21,7 +25,6 @@ import {Text} from '#/components/Typography'
 import type * as bsky from '#/types/bsky'
 import {LinkPreview} from './LinkPreview'
 import {useLiveLinkMetaQuery, useUpsertLiveStatusMutation} from './queries'
-import {displayDuration, useDebouncedValue} from './utils'
 
 export function GoLiveDialog({
   control,
@@ -57,7 +60,7 @@ function DialogInner({profile}: {profile: bsky.profile.AnyProfileView}) {
 
   const time = useCallback(
     (offset: number) => {
-      tick!
+      void tick
 
       const date = new Date()
       date.setMinutes(date.getMinutes() + offset)