Initial commit: ServerManager GUI application

CustomTkinter desktop app for managing remote servers.
Features: SSH terminal, SFTP file transfer, key management,
background status monitoring, server CRUD with dark theme.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gui/widgets/status_badge.py

@@ -0,0 +1,26 @@
+"""
+Status badge widget — colored circle indicator for online/offline.
+"""
+
+import customtkinter as ctk
+
+COLORS = {
+    "online": "#22c55e",   # green
+    "offline": "#ef4444",  # red
+    "unknown": "#6b7280",  # gray
+}
+
+
+class StatusBadge(ctk.CTkLabel):
+    def __init__(self, master, status: str = "unknown", **kwargs):
+        super().__init__(master, text="", width=12, height=12, **kwargs)
+        self._status = status
+        self._update_color()
+
+    def set_status(self, status: str):
+        self._status = status
+        self._update_color()
+
+    def _update_color(self):
+        color = COLORS.get(self._status, COLORS["unknown"])
+        self.configure(text="\u25cf", text_color=color, font=("", 14))