fix: clear actionable kagi-cli backlog

[Microck]

Summary

• refresh the remaining backlog dependency bumps by updating clap_complete to 4.6.2, toml to 1.1.2, and the stale actions/upload-artifact workflow pins to v7.0.1
• stop permanently caching failed HTTP client initialization so transient client-build failures do not poison the process
• write .kagi.toml atomically while preserving hardened file permissions
• remove the production redirect-parser unwrap() and keep unreadable error bodies diagnostic instead of silently empty

Verification

• cargo test
• cargo clippy --all-targets --all-features -- -D warnings