fix: remove src/ from gitignore

The src/ entry was intended for AUR/makepkg build artifacts but
conflicted with the actual Rust source directory.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: raaymax

.gitignore

@@ -7,6 +7,5 @@ ROADMAP.md
 # AUR/makepkg build artifacts
 *.pkg.tar.zst
 pkg/
-src/
 PKGBUILD
 .SRCINFO