Snippets: add built-in templates (collapsed "Templates" section in the snippets view and the terminal snippet panel): authorize an SSH key from the keychain for a user, install the QEMU guest agent, set/remove an APT cache server (apt-cacher-ng), system update; parameters are asked for before running

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mrterm",
-  "version": "0.13.3",
+  "version": "0.14.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mrterm",
-      "version": "0.13.3",
+      "version": "0.14.0",
       "license": "MIT",
       "dependencies": {
         "@xterm/addon-fit": "^0.11.0",