fix: session reconnect catch-up, always-on input, frozen session recovery (#524)

- WebSocketContext: emit 'websocket-reconnected' on onopen when it's a reconnect
  (hasConnectedRef tracks first-connect vs. subsequent reconnects).
- useChatRealtimeHandlers: handle 'websocket-reconnected' via onWebSocketReconnect
  callback; added to globalMessageTypes to bypass sessionId mismatch checks.
- ChatInterface: on reconnect, re-fetch JSONL session history so messages missed
  during iOS background are shown immediately. Also resets isLoading and
  canAbortSession so a dead/restarted session no longer freezes the UI forever.
- ChatComposer: remove disabled={isLoading} from textarea — users can always
  type regardless of processing state; submit button still prevents double-send.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/chat/view/subcomponents/ChatComposer.tsx

@@ -301,8 +301,7 @@ export default function ChatComposer({
               onBlur={() => onInputFocusChange?.(false)}
               onInput={onTextareaInput}
               placeholder={placeholder}
-              disabled={isLoading}
-              className="chat-input-placeholder block max-h-[40vh] min-h-[50px] w-full resize-none overflow-y-auto rounded-2xl bg-transparent py-1.5 pl-12 pr-20 text-base leading-6 text-foreground placeholder-muted-foreground/50 transition-all duration-200 focus:outline-none disabled:opacity-50 sm:max-h-[300px] sm:min-h-[80px] sm:py-4 sm:pr-40"
+              className="chat-input-placeholder block max-h-[40vh] min-h-[50px] w-full resize-none overflow-y-auto rounded-2xl bg-transparent py-1.5 pl-12 pr-20 text-base leading-6 text-foreground placeholder-muted-foreground/50 transition-all duration-200 focus:outline-none sm:max-h-[300px] sm:min-h-[80px] sm:py-4 sm:pr-40"
               style={{ height: '50px' }}
             />