Release v0.5.0

✨ New Features

Terminal color schemes: 13 built-in schemes (rustXterm light/dark, Solarized Dark/Light, Dracula, Gruvbox Dark/Light, Nord, One Dark, Monokai, Tango Dark/Light, xterm), picked globally or per session, with a color swatch preview in the picker.
Custom color schemes: drop JSON files into schemes/ next to config.toml (~/.config/rustxterm/schemes/, %APPDATA%\rustxterm\schemes\); invalid, oversized (> 64 KiB) and duplicate-name files are skipped with a log warning.
Per-session "Follow UI theme" override, even when the global scheme is fixed.
Font zoom shortcuts Ctrl+= / Ctrl++ / Ctrl+- / Ctrl+0 next to Ctrl+wheel; the size is saved (globally, or to the session when it has its own font size), applies to every open tab using it and is restored on the next start.

Zoom steps by exactly one point (6 to 48); Ctrl+_ and Ctrl+/ send 0x1f to the shell.
Session banner hint lists the keyboard zoom keys.

Root README kept short; color schemes, custom scheme format and zoom in docs/README.md.
New screenshots (Dracula terminal, scheme picker) and refreshed gallery.
OpenSpec: add-terminal-color-schemes change.

rustxterm-0.5.0-x86_64 portable binary (glibc >= 2.31)
rustxterm-0.5.0-x86_64.AppImage
rustxterm-0.5.0-x86_64.tar.gz (binary, .desktop, icon, licenses)
rustxterm-0.5.0-windows-x86_64.zip and rustxterm-0.5.0-x86_64.msi (Windows x86_64, preview, unsigned)
SHA256SUMS, provenance.json

Full Changelog: v0.4.0...v0.5.0