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/features/liveEvents/components/LiveEventFeedOptionsMenu.tsx

@@ -9,7 +9,7 @@ import {Admonition} from '#/components/Admonition'
 import {Button, ButtonIcon, ButtonText} from '#/components/Button'
 import * as Dialog from '#/components/Dialog'
 import {Loader} from '#/components/Loader'
-import * as toast from '#/components/Toast'
+import * as Toast from '#/components/Toast'
 import {Span, Text} from '#/components/Typography'
 import {useUpdateLiveEventPreferences} from '#/features/liveEvents/preferences'
 import {
@@ -61,14 +61,14 @@ function Inner({
     feed,
     metricContext,
     onUpdateSuccess({undoAction}) {
-      toast.show(
-        <toast.Outer>
-          <toast.Icon />
-          <toast.Text>
+      Toast.show(
+        <Toast.Outer>
+          <Toast.Icon />
+          <Toast.Text>
             <Trans>Your live event preferences have been updated.</Trans>
-          </toast.Text>
+          </Toast.Text>
           {undoAction && (
-            <toast.Action
+            <Toast.Action
               label={_(msg`Undo`)}
               onPress={() => {
                 if (undoAction) {
@@ -76,12 +76,10 @@ function Inner({
                 }
               }}>
               <Trans>Undo</Trans>
-            </toast.Action>
+            </Toast.Action>
           )}
-        </toast.Outer>,
-        {
-          type: 'success',
-        },
+        </Toast.Outer>,
+        {type: 'success'},
       )
 
       /*