v0.9.1

Features:
- WLED auto-detection: LED count, RGB order via JSON API
- WLED mDNS discovery with target = "auto"
- Idle timeout: close output after N minutes of silence

Performance:
- Ring buffer bulk-copy (~27x faster push/pop_slice)

Fixes:
- Shutdown hang in PipeWire and FIFO audio backends (#3)

Add CI/CD, GPL-3.0 license, .deb packaging, and project config

- GitHub Actions CI: build, test, clippy, fmt, cross-check (pinned Rust 1.94.0)
- GitHub Actions Release: binaries + .deb packages for amd64, arm64, armhf
- GPL-3.0 license with SPDX headers in all source files
- cargo-deb metadata, systemd service, postinst script
- One-line install script for Raspberry Pi users
- Cross.toml for ARM cross-compilation