v1.8.52: icons module, Windows SSH sanitization, embedded RDP improvements, UI polish

- Add core/icons.py — centralized icon text helper with emoji/symbol support
- Add Windows SSH command sanitization in ssh.py (Linux→Windows auto-translation)
- Improve embedded RDP: launch tab connect/disconnect, fullscreen toggle
- Refactor sidebar: cleaner server type badges
- Update server_dialog: adaptive fields per server type
- Add setup_openssh.bat tool
- Update skill-ssh.md and CLAUDE.md docs for Windows SSH support
- Cleanup old releases, add v1.8.48-v1.8.52

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

gui/tabs/keys_tab.py

@@ -7,6 +7,7 @@ import threading
 import customtkinter as ctk
 from core.ssh_client import SSHClientWrapper
 from core.i18n import t
+from core.icons import icon_text
 
 
 class KeysTab(ctk.CTkFrame):
@@ -29,13 +30,13 @@ class KeysTab(ctk.CTkFrame):
         btn_frame = ctk.CTkFrame(self, fg_color="transparent")
         btn_frame.pack(fill="x", padx=15, pady=5)
 
-        self.gen_btn = ctk.CTkButton(btn_frame, text=t("generate_key"), command=self._generate)
+        self.gen_btn = ctk.CTkButton(btn_frame, text=icon_text("key", t("generate_key")), command=self._generate)
         self.gen_btn.pack(side="left", padx=(0, 10))
 
-        self.install_btn = ctk.CTkButton(btn_frame, text=t("install_on_server"), fg_color="#22c55e", hover_color="#16a34a", command=self._install)
+        self.install_btn = ctk.CTkButton(btn_frame, text=icon_text("upload", t("install_on_server")), fg_color="#22c55e", hover_color="#16a34a", command=self._install)
         self.install_btn.pack(side="left")
 
-        self.copy_btn = ctk.CTkButton(btn_frame, text=t("copy_public_key"), fg_color="#6b7280", command=self._copy_key)
+        self.copy_btn = ctk.CTkButton(btn_frame, text=icon_text("copy", t("copy_public_key")), fg_color="#6b7280", command=self._copy_key)
         self.copy_btn.pack(side="right")
 
         # Status log