Add icons for various packages and update package.json files

- Added SVG icons for the following packages:
  - github_tools
  - irc_webchat
  - json_script_example
  - lua_test
  - media_center
  - nav_menu
  - notification_center
  - package_validator
  - quick_guide
  - role_editor
  - schema_editor
  - screenshot_analyzer
  - smtp_config
  - social_hub
  - stats_grid
  - stream_cast
  - ui_auth
  - ui_dialogs
  - ui_footer
  - ui_header
  - ui_home
  - ui_intro
  - ui_level2
  - ui_level3
  - ui_level4
  - ui_level5
  - ui_level6
  - ui_login
  - ui_pages
  - ui_permissions
  - user_manager
  - workflow_editor

- Updated package.json files to include icon paths for each package.

packages/json_script_example/package.json

@@ -7,6 +7,7 @@
   "author": "MetaBuilder",
   "license": "MIT",
   "category": "examples",
+  "icon": "static_content/icon.svg",
   "minLevel": 0,
   "primary": false,
   "dependencies": {},

packages/json_script_example/static_content/icon.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+  <!-- JSON curly braces with document -->
+  <rect x="20" y="14" width="24" height="36" rx="2" fill="none"/>
+  <path d="M16 22 C14 22 12 24 12 26 L12 30 C12 32 10 32 10 34 C10 36 12 36 12 38 L12 42 C12 44 14 46 16 46" stroke-width="2"/>
+  <path d="M48 22 C50 22 52 24 52 26 L52 30 C52 32 54 32 54 34 C54 36 52 36 52 38 L52 42 C52 44 50 46 48 46" stroke-width="2"/>
+</svg>