Improve context handling

[thelovekesh]

• Improve context handling
• Add atomicwriter.WriteFile to write state files in a atomic way

[github-actions]

📦 wpm cli builds 📦

• darwin/amd64 - build
• darwin/arm64 - build
• linux/amd64 - build
• linux/arm/v6 - build
• linux/arm/v7 - build
• linux/arm64 - build
• linux/ppc64le - build
• linux/riscv64 - build
• linux/s390x - build
• windows/amd64 - build
• windows/arm64 - build

[gemini-code-assist]

Code Review

This pull request comprehensively improves context propagation across the CLI, archiving utilities, and API clients to ensure context cancellation (such as SIGINT) is properly honored. It also introduces a new atomicwriter package to write configuration and lockfiles atomically, improves HTTP connection reuse by draining response bodies, limits error body read sizes, and cleans up stale cache files. The reviewer feedback suggests replacing time.After with time.NewTimer in the retry loop of renameFile to prevent potential short-term timer leaks.