Version bump 0.4.0 -> 0.5.0 (Cargo.toml/lock, Windows .iss, PKGBUILD placeholder) and a new CHANGELOG.md covering the 21 commits since v0.4.0 (A9 context menu, W21 selectable text, A25 clock-skew, A23 screen-share per-app audio, A15 reliable critical commands, A24 per-peer volume, Tier-C security caps, Debian/Arch packaging). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>