Prepare v0.5.8 with configurable long date format

[chaqchase]

Summary

• Add a configurable long-view date format via --date-format and [formatters.long].date_format
• Keep the existing %b %d %H:%M output by default while allowing formats like %Y-%m-%d %H:%M
• Preserve --relative-dates precedence over custom absolute date formatting
• Fix the related --no-color symbolic permission regression in long/table/fuzzy output
• Prepare release v0.5.8 by bumping workspace/plugin versions, internal dependency versions, Cargo.lock, and CHANGELOG.md

Closes #162.

Validation

• cargo fmt --all -- --check
• cargo check --workspace
• cargo test --workspace
• cargo run -p lla -- -la --no-color --date-format "%Y-%m-%d %H:%M" lla/src
• git diff --check
• GitHub Actions CI: all 7 checks passing on run 28713748401

Release

This PR is labeled release. After it merges to main, the release workflow should use the prepared workspace version 0.5.8 to publish v0.5.8.