refactor(api): split monolithic handlers.go into focused modules

Break down the 627-line handlers.go into specialized modules:
- handlers_chat.go: chat and streaming endpoints
- handlers_config.go: configuration endpoints
- handlers_common.go: shared utilities
- handlers_info.go: info and status endpoints
- handlers_terminal.go: terminal/shell endpoints
- handlers_tools.go: tool-related endpoints

Also includes config improvements, orchestrator enhancements, and
web component updates.

💘 Generated with Crush

Assisted-by: MiniMax-M2.7 via Crush <crush@charm.land>

web/src/components/Studio.jsx

@@ -178,9 +178,10 @@ export default function Studio({ api }) {
 
     try {
       let accumulated = ''
-      await api.sendChat(text, true).then(full => {
-        accumulated = full
-      }).catch(() => {})
+      await api.sendChat(text, true, (partial) => {
+        accumulated = partial
+        setStreaming(partial)
+      })
 
       const finalContent = accumulated || t('studio.noResponse')
       setMessages(prev => [...prev, {