Add reproducible build system, native Unraid plugin, and WebUI

- versions.env pins podman, conmon, crun, netavark, aardvark-dns, passt,
  and fuse-overlayfs to verified upstream source checksums; SlackBuild
  recipes, scripts/build-packages.sh, checksums.sh, release.sh, and
  update-versions.sh implement the reproducible pipeline; GitHub Actions
  workflows build in a Slackware container and publish releases without
  committing any binaries.

- plugin/podman.plg installs/updates/removes all eight packages (the
  seven components plus the plugin's own unraid-podman scaffolding
  package) via upgradepkg, using the official Unraid array-event hook
  mechanism (event/disks_mounted, event/stopping) instead of editing
  /boot/config/go. rc.podman and the sbin/ helper scripts implement
  storage creation, config seeding/sync, preflight checks, autostart
  with per-container Safe-Mode, and package verify/update/rollback.

- webui/plugins/podman implements the Dashboard, Containers, Pods,
  Images, Volumes, Networks, Logs, Terminal, Compose, and Settings
  panels against the approved mockup (webui/mockups/prototype.html),
  talking to podman system service exclusively via PodmanClient.php
  (libpod REST API over the Unix socket), with two documented
  exceptions: Terminal's one-shot exec model and Compose's use of the
  podman compose CLI, since libpod has no REST equivalent for either.

- docs/ARCHITECTURE.md and docs/ROADMAP.md record the design decisions
  and honest current status (syntax-checked, unit- and
  integration-tested against fake sockets/servers; not yet run against
  a real Unraid/Podman/Slackware system).

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

packages/aardvark-dns/aardvark-dns.SlackBuild

@@ -0,0 +1,46 @@
+#!/bin/bash
+# =============================================================================
+# packages/aardvark-dns/aardvark-dns.SlackBuild
+#
+# Builds the aardvark-dns .txz package from upstream source (Rust).
+# aardvark-dns provides container-to-container DNS name resolution within
+# netavark-managed networks (see docs/ARCHITECTURE.md section 8). Installed
+# as a libexec helper binary, same rationale as netavark.
+#
+# Requires (in the build environment): rustc, cargo.
+# =============================================================================
+
+set -eu
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+# shellcheck source=/dev/null
+. "$REPO_ROOT/scripts/lib/slackbuild-common.sh"
+# shellcheck source=/dev/null
+. "$REPO_ROOT/versions.env"
+
+VERSION="$AARDVARK_DNS_VERSION"
+ARCH="$PKG_ARCH"
+BUILD="$PKG_BUILD"
+TAG="$PKG_TAG"
+
+sb_init "aardvark-dns"
+
+tarball=$(sb_fetch_and_verify "$AARDVARK_DNS_SRC_URL" "$AARDVARK_DNS_SRC_SHA256" "aardvark-dns-$VERSION.tar.gz")
+srcdir=$(sb_extract "$tarball")
+
+for patch in "$CWD"/patches/*.patch; do
+  [ -e "$patch" ] || continue
+  echo "==> [aardvark-dns] applying $(basename "$patch")"
+  patch -d "$srcdir" -p1 < "$patch"
+done
+
+cd "$srcdir"
+
+echo "==> [aardvark-dns] cargo build --release"
+cargo build --release --locked
+
+echo "==> [aardvark-dns] install into \$PKG"
+install -D -m 0755 target/release/aardvark-dns "$PKG/usr/libexec/podman/aardvark-dns"
+
+sb_install_docs "$srcdir/LICENSE" "$srcdir/README.md"
+sb_make_package "$VERSION" "$ARCH" "$BUILD" "$TAG"