chore: update macOS binary and process name to Decentraland

[aixaCode]

Summary

• Aligns launcher-rust with the Unity productName rename in decentraland/unity-explorer#8207, which changes the product name from Explorer to Decentraland.
• Updates the macOS post-install chmod path from Decentraland.app/Contents/MacOS/Explorer to .../MacOS/Decentraland so the installed binary gets marked executable.
• Updates the macOS running-instance tracking name from Explorer to Decentraland so the launcher correctly finds the running process after the rename.
• Windows is unaffected — EXPLORER_WIN_BIN_PATH was already Decentraland.exe.

Coordination

• Must land after unity-explorer#8207 ships in a build. If this PR is released against older explorer builds, macOS installs will break: the binary won't be chmod'd and running-instance tracking won't find the process.
• Recommend gating the release of this change behind the first explorer build that contains the productName rename.

Test plan

• CI builds green
• Manually verify on macOS against a build from unity-explorer#8207: install completes, binary is executable, launcher detects the running Decentraland process
• Manually verify on Windows that launching still works unchanged

[github-actions]

Windows and Mac build successful in Launcher Rust!! You can find a link to the downloadable artifact below.

Name	Link
Commit	46a8ac9
Download Plain Windows S3	dcl_launcher.exe
Download Windows S3	Decentraland_installer.exe
Download Mac S3	Decentraland_installer.dmg
Built on	2026-04-13T12:34:37Z