chore: bump pawan to v0.5.23

[bkataru]

Summary

• bump workspace crates, lockfile, docs, API example, and TUI welcome snapshots to v0.5.23
• release the CARGO_REGISTRY_TOKEN preflight hardening from Unreleased into v0.5.23
• track release progress in Linear DIR1-96

Verification

• duf /opt /tmp
• dust -d 1 /opt/pawan
• cargo fmt --all
• release workflow YAML/preflight assertions, including missing-token shell path exiting 1 with the intended error
• cargo check --workspace
• cargo test -p pawan test_render_welcome_snapshot
• cargo test -p pawan --test regression_smoke
• cargo test -p pawan --test tui_headless_tests -- --nocapture
• cargo clippy --workspace --all-targets
• RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps --document-private-items
• cargo test --workspace --no-fail-fast (1827 passed, 14 ignored)
• restored repository CARGO_REGISTRY_TOKEN secret; gh secret list --repo dirmacs/pawan shows it present

Linear: DIR1-96