add retries when package fails to build

[Samueru-sama]

the opus package often fails due to connection issues.

[Copilot]

Pull Request Overview

This PR adds retry logic for package builds that frequently fail due to connection issues, particularly for the opus package. The changes implement a standardized cleanup mechanism across all build scripts and add a retry loop in the CI workflow.

• Implements consistent temporary build directory management across all build scripts
• Adds signal traps for cleanup on script interruption or exit
• Introduces a retry mechanism in CI that attempts builds up to 3 times before failing

Reviewed Changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
qt6-base-mini.sh	Adds tmpbuild directory and cleanup trap
opus-mini.sh	Adds tmpbuild directory and cleanup trap
mesa-nano.sh	Adds tmpbuild directory and cleanup trap
mesa-mini.sh	Adds tmpbuild directory and cleanup trap
mangohud-mini.sh	Refactors to use tmpbuild directory and cleanup trap
llvm-nano.sh	Adds tmpbuild directory and cleanup trap
llvm-mini.sh	Adds tmpbuild directory and cleanup trap
libxml2-mini.sh	Adds tmpbuild directory and cleanup trap
intel-media-driver-mini.sh	Adds tmpbuild directory and cleanup trap
gtk4-mini.sh	Adds tmpbuild directory and cleanup trap
gtk3-mini.sh	Adds tmpbuild directory and cleanup trap
ffmpeg-mini.sh	Adds tmpbuild directory and cleanup trap
.github/workflows/blank.yml	Implements retry logic for package builds with up to 3 attempts

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