Add plasmoid scaffold: metadata.json + config schema

Plasma/Applet package metadata (tray applet, id sk.houmeres.synologynas)
and the KConfigXT schema (hosts JSON, mount root, SMB version, options).
Passwords are never stored in config — they live in KWallet.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package/metadata.json

@@ -0,0 +1,24 @@
+{
+    "KPackageStructure": "Plasma/Applet",
+    "KPlugin": {
+        "Authors": [
+            {
+                "Name": "Houmeres"
+            }
+        ],
+        "Category": "Utilities",
+        "Description": "Browse, mount and unmount Synology / SMB (CIFS) network shares from the system tray.",
+        "EnabledByDefault": true,
+        "Icon": "folder-network",
+        "Id": "sk.houmeres.synologynas",
+        "License": "MIT",
+        "Name": "Synology NAS",
+        "Version": "0.1.0",
+        "Website": "https://git.houmeres.sk/Houmeres/Plasma-Addon-Synology-NAS"
+    },
+    "X-Plasma-API": "declarativeappletscript",
+    "X-Plasma-API-Minimum-Version": "6.0",
+    "X-Plasma-MainScript": "ui/main.qml",
+    "X-Plasma-NotificationArea": "true",
+    "X-Plasma-NotificationAreaCategory": "SystemServices"
+}