devex: dead locales cleanup + i18n inspect tool (#5313)

* chore: remove old locales + just enable all locales now

* feat: debug panel for i18n + tooltips

* feat: dedupe

* fix: debugger for app

* fix: crowdin code mismatches

* fix: lint

apps/frontend/src/plugins/i18n-debug.client.ts

@@ -0,0 +1,50 @@
+import {
+	annotateFullDocument,
+	clearAllAnnotations,
+	hideKeyTooltip,
+	I18N_DEBUG_KEY,
+	type I18nDebugContext,
+	initI18nDebugRuntime,
+} from '@modrinth/ui'
+
+export default defineNuxtPlugin({
+	name: 'i18n-debug',
+	enforce: 'post',
+	setup(nuxtApp) {
+		const flags = useFeatureFlags()
+		if (!flags.value.i18nDebug) return
+
+		const enabled = ref(true)
+		const keyReveal = ref(false)
+		const registry = reactive(new Map()) as Map<
+			string,
+			{ key: string; value: string; defaultMessage?: string; timestamp: number }
+		>
+		const panelOpen = ref(false)
+
+		const context: I18nDebugContext = { enabled, keyReveal, registry, panelOpen }
+		nuxtApp.vueApp.provide(I18N_DEBUG_KEY, context)
+
+		nuxtApp.hook('app:mounted', () => {
+			initI18nDebugRuntime(context)
+		})
+
+		watch(
+			() => flags.value.i18nDebug,
+			(active) => {
+				enabled.value = active
+				if (!active) {
+					keyReveal.value = false
+					panelOpen.value = false
+					document.body.classList.remove('i18n-debug')
+					clearAllAnnotations()
+					hideKeyTooltip()
+					registry.clear()
+				} else {
+					document.body.classList.add('i18n-debug')
+					annotateFullDocument(registry)
+				}
+			},
+		)
+	},
+})