v1.9.0: S3 server type — bucket/object browser, drag-and-drop upload, resilient transfers

New server type: S3 (MinIO, AWS, any S3-compatible storage)
- core/s3_client.py: boto3 client with auto-reconnect, 10 retries, exponential backoff, multipart upload/download, tcp_keepalive
- gui/tabs/s3_tab.py: object browser (Treeview), bucket selector, folder navigation, drag-and-drop upload from Explorer (windnd), progress bar with %, multi-file upload
- CLI: --s3-buckets, --s3-ls, --s3-upload, --s3-download, --s3-delete with retry
- ServerDialog: access_key, secret_key, bucket fields
- Registration: server_store, connection_factory, status_checker, icons, app, i18n (EN/RU/ZH)
- Fix: build.py cleanup_old_releases now sorts by semver (was lexicographic, broke v1.8.100+)

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

gui/server_dialog.py

@@ -24,6 +24,7 @@ FIELD_MAP = {
     "prometheus": ["use_ssl"],
     "rdp":        ["user", "password", "rdp_resolution", "rdp_quality", "rdp_clipboard", "rdp_drives", "rdp_printers"],
     "vnc":        ["password"],
+    "s3":         ["access_key", "secret_key", "bucket", "use_ssl"],
 }
 
 
@@ -242,6 +243,27 @@ class ServerDialog(ctk.CTkToplevel):
         ctk.CTkCheckBox(f, text=t("rdp_printers"), variable=self._rdp_printers_var).pack(fill="x", padx=20, pady=(4, 2))
         self._field_frames["rdp_printers"] = f
 
+        # --- access_key ---
+        f = ctk.CTkFrame(self, fg_color="transparent")
+        ctk.CTkLabel(f, text=t("access_key"), anchor="w").pack(fill="x", **pad)
+        self.access_key_entry = ctk.CTkEntry(f, placeholder_text="AKIAIOSFODNN7EXAMPLE")
+        self.access_key_entry.pack(fill="x", **entry_pad)
+        self._field_frames["access_key"] = f
+
+        # --- secret_key ---
+        f = ctk.CTkFrame(self, fg_color="transparent")
+        ctk.CTkLabel(f, text=t("secret_key"), anchor="w").pack(fill="x", **pad)
+        self.secret_key_entry = ctk.CTkEntry(f, show="*", placeholder_text=t("placeholder_secret_key"))
+        self.secret_key_entry.pack(fill="x", **entry_pad)
+        self._field_frames["secret_key"] = f
+
+        # --- bucket ---
+        f = ctk.CTkFrame(self, fg_color="transparent")
+        ctk.CTkLabel(f, text=t("bucket"), anchor="w").pack(fill="x", **pad)
+        self.bucket_entry = ctk.CTkEntry(f, placeholder_text="my-bucket")
+        self.bucket_entry.pack(fill="x", **entry_pad)
+        self._field_frames["bucket"] = f
+
         # --- use_ssl ---
         f = ctk.CTkFrame(self, fg_color="transparent")
         self.use_ssl_var = ctk.BooleanVar(value=False)
@@ -282,6 +304,9 @@ class ServerDialog(ctk.CTkToplevel):
             self.db_index_entry.insert(0, str(server.get("db_index", "")))
             self.api_token_entry.insert(0, server.get("api_token", ""))
             self.use_ssl_var.set(server.get("use_ssl", False))
+            self.access_key_entry.insert(0, server.get("access_key", ""))
+            self.secret_key_entry.insert(0, server.get("secret_key", ""))
+            self.bucket_entry.insert(0, server.get("bucket", ""))
 
             # RDP settings
             res_raw = server.get("rdp_resolution", "auto")
@@ -411,6 +436,21 @@ class ServerDialog(ctk.CTkToplevel):
             if token:
                 server_data["api_token"] = token
 
+        if "access_key" in visible:
+            ak = self.access_key_entry.get().strip()
+            if ak:
+                server_data["access_key"] = ak
+
+        if "secret_key" in visible:
+            sk = self.secret_key_entry.get()
+            if sk:
+                server_data["secret_key"] = sk
+
+        if "bucket" in visible:
+            bkt = self.bucket_entry.get().strip()
+            if bkt:
+                server_data["bucket"] = bkt
+
         if "use_ssl" in visible:
             if self.use_ssl_var.get():
                 server_data["use_ssl"] = True