chore: bump version to 0.4.2, update changelog and readme

fix: validate animation name before entering raw mode

Unknown animation names now print a clean error with the full list of
available animations and exit with code 1, instead of panicking and
leaving the terminal in raw mode.

Bumps version to 0.4.1.

Update GitHub Sponsors username in FUNDING.yml

fix: close BSU sync block on exit to prevent terminal freeze

Every frame is wrapped in \x1b[?2026h / \x1b[?2026l (Synchronized Output).
When quit fires mid-write, the terminal receives the begin marker but not
the end marker. It enters sync mode and buffers all subsequent data —
including the restore sequences — so the cursor stays hidden and the alt
screen stays active. Terminal appears frozen on the last frame.

Prepend \x1b[?2026l to the restore write to close any pending sync block.
Safe to send when not in sync mode (no-op). Fixes freeze in all quit paths.

Fix Windows build: cfg-gate Unix-only chunked writes

The libc::write chunked output and AsRawFd are Unix-only. Windows
falls back to standard Rust write_all + flush.

Update Rust to 1.93.1, unify CI/release toolchain