Add metadata and install/uninstall automation for Thunderbird on
Windows. Adds ee/maintained-apps/inputs/winget/thunderbird.json plus
PowerShell install/uninstall scripts (NSIS silent /S, install uses
/PreventRebootRequired=true; uninstall resolves registry entry for x64
en-US and appends /S). Update maintained apps outputs: register
Thunderbird in ee/maintained-apps/outputs/apps.json and add
ee/maintained-apps/outputs/thunderbird/windows.json (version 149.0.2,
installer URL and sha256, script refs). Also update frontend icon
component and app PNG asset for Thunderbird.
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**Related issue:** Resolves#43526
Allen Houchins
10a7476ecc