Pre-0.1 cleanup: fmt, docs, licenses, AUR-ready packaging

- cargo fmt across the workspace (the CI gate the last push tripped).
- varde-daemon: drop the now-unused bytes dependency.
- varde-ctl(1): document push; gc reflects the continuous-sweep
  reality; subscribe mentions push events.
- config.toml example: gc_interval_secs, and an honest note that
  max_download_bytes_per_sec is currently unenforced.
- LICENSE-MIT + LICENSE-APACHE at the root (the declared license now
  ships as files), bundled into release tarballs and installed by the
  PKGBUILD.
- PKGBUILD: real maintainer, AUR pre-flight note (updpkgsums), license
  installation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -55,7 +55,7 @@ jobs:
           cp dist/config.toml "$PKG/config.toml.example"
           scdoc < dist/varde.8.scd > "$PKG/man/varde.8"
           scdoc < dist/varde-ctl.1.scd > "$PKG/man/varde-ctl.1"
-          cp README.md SPECS.md "$PKG/"
+          cp README.md SPECS.md LICENSE-MIT LICENSE-APACHE "$PKG/"
           tar czf "$PKG.tar.gz" "$PKG"
           sha256sum "$PKG.tar.gz" > "$PKG.tar.gz.sha256"