feat(i18n): extract remaining screens into en/zh-Hans catalogs; full Simplified Chinese coverage (closes #68) (#103)

Extends the i18n infra from #97 (Settings screen only) to the rest of the
app: session chat screen, connection add/edit/list screens, sessions list
(incl. directory grouping from #96), navigation titles, notifications
category metadata, error boundary, telemetry consent modal, auth gate, and
every chat UI component (permission/question prompts, status indicator,
model/variant pickers, directory switcher/browser, reasoning block, tool
call card, session info).

- 244 new keys added to en.json/zh-Hans.json with reviewed, natural
  Simplified Chinese (not machine-garbage), keeping key sets identical.
- User content, server URLs, code snippets, log/error-detail text, and
  diagnostics-classify.ts (pure dependency-free module feeding Sentry/
  support reports) are intentionally left untranslated per scope.
- Interpolation used for counts/names (e.g. reconnect attempt, files
  count, connection name in delete confirmations); categoryMeta/
  CONNECTION_TYPES switched to labelKey indirection since they're
  module-level constants evaluated before i18next is guaranteed ready.
- Added src/lib/i18n/catalog-parity.test.ts (node --test) asserting
  en.json/zh-Hans.json expose identical key sets and no empty values,
  to catch future locale drift.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

src/components/chat/SlashPopover.tsx

@@ -1,6 +1,7 @@
 import { useMemo } from "react"
 import { View, Text, TouchableOpacity, ScrollView, StyleSheet, Keyboard, Platform } from "react-native"
 import { Ionicons } from "@expo/vector-icons"
+import { useTranslation } from "react-i18next"
 
 export interface SlashCommand {
   trigger: string
@@ -18,6 +19,7 @@ interface Props {
 }
 
 export function SlashPopover({ query, commands, isDark, onSelect }: Props) {
+  const { t } = useTranslation()
   const filtered = useMemo(() => {
     const q = query.toLowerCase()
     return commands.filter((c) => c.trigger.toLowerCase().startsWith(q) || c.title.toLowerCase().includes(q))
@@ -45,7 +47,7 @@ export function SlashPopover({ query, commands, isDark, onSelect }: Props) {
             </View>
             {cmd.type === "custom" && (
               <View style={[s.badge, isDark && s.badgeDark]}>
-                <Text style={s.badgeText}>cmd</Text>
+                <Text style={s.badgeText}>{t("chat.slashPopover.customBadge")}</Text>
               </View>
             )}
           </TouchableOpacity>