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>

internal/api/conversation.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"encoding/json"
+	"fmt"
 	"os"
 	"path/filepath"
 	"sync"
@@ -153,5 +154,5 @@ func (cs *ConversationStore) NeedsSummarization() bool {
 }
 
 func generateMsgID() string {
-	return time.Now().Format("20060102150405.000")
+	return time.Now().Format("20060102150405.000") + "-" + fmt.Sprintf("%d", time.Now().UnixNano())
 }