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>

LICENSE-MIT

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Bendik Lynghaug
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.