fix(desktop): restore custom chat window header

Revert to frameless window with custom header containing
minimize/close buttons and drag region.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/desktop/src-tauri/src/chat.rs

@@ -718,9 +718,9 @@ fn open_chat_window_internal(app: &tauri::AppHandle, ticket_id: &str) -> Result<
     .inner_size(380.0, 520.0)
     .min_inner_size(300.0, 400.0)
     .position(x, y)
-    .decorations(true) // Usar decoracoes nativas do Windows
+    .decorations(false) // Sem decoracoes nativas - usa header customizado
     .always_on_top(true)
-    .skip_taskbar(false) // Mostrar na taskbar
+    .skip_taskbar(true)
     .focused(true)
     .visible(true)
     .build()

apps/desktop/src/chat/ChatWidget.tsx

@@ -4,7 +4,7 @@ import { listen } from "@tauri-apps/api/event"
 import { Store } from "@tauri-apps/plugin-store"
 import { appLocalDataDir, join } from "@tauri-apps/api/path"
 import { open } from "@tauri-apps/plugin-dialog"
-import { Send, X, Loader2, Headphones, Paperclip, FileText, Image as ImageIcon, File } from "lucide-react"
+import { Send, X, Minus, Loader2, Headphones, Paperclip, FileText, Image as ImageIcon, File } from "lucide-react"
 import type { ChatMessage, ChatMessagesResponse, SendMessageResponse } from "./types"
 
 const STORE_FILENAME = "machine-agent.json"
@@ -291,6 +291,14 @@ export function ChatWidget({ ticketId }: ChatWidgetProps) {
     }
   }
 
+  const handleMinimize = () => {
+    invoke("minimize_chat_window", { ticketId })
+  }
+
+  const handleClose = () => {
+    invoke("close_chat_window", { ticketId })
+  }
+
   const handleKeyDown = (e: React.KeyboardEvent) => {
     if (e.key === "Enter" && !e.shiftKey) {
       e.preventDefault()
@@ -325,8 +333,12 @@ export function ChatWidget({ ticketId }: ChatWidgetProps) {
 
   return (
     <div className="flex h-screen flex-col bg-white">
-      {/* Header */}
-      <div className="flex items-center gap-3 border-b border-slate-200 bg-slate-50 px-4 py-3">
+      {/* Header - arrastavel */}
+      <div
+        data-tauri-drag-region
+        className="flex items-center justify-between border-b border-slate-200 bg-slate-50 px-4 py-3"
+      >
+        <div className="flex items-center gap-3">
           <div className="flex size-10 items-center justify-center rounded-full bg-black text-white">
             <Headphones className="size-5" />
           </div>
@@ -341,6 +353,21 @@ export function ChatWidget({ ticketId }: ChatWidgetProps) {
             )}
           </div>
         </div>
+        <div className="flex items-center gap-1">
+          <button
+            onClick={handleMinimize}
+            className="rounded p-1.5 text-slate-400 hover:bg-slate-200 hover:text-slate-600"
+          >
+            <Minus className="size-4" />
+          </button>
+          <button
+            onClick={handleClose}
+            className="rounded p-1.5 text-slate-400 hover:bg-slate-200 hover:text-slate-600"
+          >
+            <X className="size-4" />
+          </button>
+        </div>
+      </div>
 
       {/* Mensagens */}
       <div className="flex-1 overflow-y-auto p-4">