fix(packaging): 打包带上计费插件，并修复一个让所有产物校验形同虚设的缺陷

发 v1.8.0 时发现包里没有 billing.lua —— 而 v1.8.0 的主打特性就是计费插件，
发布说明明写「随核心发布的示例插件（billing）」。

功能本身没坏：internal/lua/vm.go 用 //go:embed plugins/*.lua 把插件编进二进制，
writeBundledPlugins 在 plugin_dir 不存在时把它写出来。实测确认（用正确格式的
配置）：全新 plugin_dir 启动后自动生成 billing.lua 70031 字节，插件正常加载。
所以这是产物内容与发布说明不符，不是功能缺失 —— 运维解包检查时看不到它，
只能等首次启动后才发现。

三处改动：

1) tar.gz 现在带 plugins/。让运维能在安装前读它、改它，而不是启动后才知道。

2) 修复 dpkg-deb 那行。`dpkg-deb -I "$DIST"/llmsproxy_*.deb` 的 glob 展开成三个
   .deb（dist 里堆着 1.5.9 / 1.6.0 / 本次产物），dpkg-deb 只认第一个归档，其余
   参数被当成 control component 名，退出码 2。脚本是 set -euo pipefail，于是
   在这里直接终止 —— 「done」从未打印，我加在后面的产物内容校验从来没有执行过，
   真正跑过的只有上面那道 100KB 大小下限。改为取最新的那个 deb。
   这个缺陷早于本次改动，是被它暴露出来的。

3) 新增产物内容校验：tar.gz 必须含 llmsproxy / config.example.yaml /
   llmsproxy.service / plugins/billing.lua，adapters 至少 10 个 .lua。
   大小下限抓不到这个问题 —— 少 70KB 仍然远超 100KB，而首次启动自动 seed 的
   行为会在运行时把它藏起来，运维看到插件正常工作就以为包是完整的。
   目录按内容而非名字匹配：tar 列出的是 …/adapters/openai.lua，不存在裸
   …/adapters 条目，第一版按名字 grep 把完整包判成了坏包。

两个变异验证：去掉 plugins 拷贝 → 「archive is missing plugins/billing.lua」
退出 1；只留 1 个 adapter → 「archive has only 1 adapters」退出 1。

packaging/core-dist.sh

@@ -77,6 +77,21 @@ cp "$ROOT/packaging/config.example.yaml" "$TAR_DIR/config.example.yaml"
 cp "$ROOT/packaging/llmsproxy.service" "$TAR_DIR/llmsproxy.service"
 mkdir -p "$TAR_DIR/adapters"
 cp "$ROOT"/internal/lua/adapters/*.lua "$TAR_DIR/adapters/"
+
+# The shipped plugins go into the archive too, not just into the binary's
+# embedded FS.
+#
+# Seeding works without them (internal/lua/vm.go embeds plugins/*.lua and
+# writeBundledPlugins materialises them on first start — verified: a fresh
+# plugin_dir gains billing.lua, 70031 bytes, and the plugin loads), so this is
+# not a functional fix. It is a contents/claim mismatch: the v1.8.0 release
+# notes tell the operator the billing plugin ships with the core, and this
+# archive — the artefact they unpack and inspect — did not contain it. Shipping
+# the file also means an operator can read and adapt it before installing,
+# instead of only discovering it after the first boot writes it out.
+mkdir -p "$TAR_DIR/plugins"
+cp "$ROOT"/internal/lua/plugins/*.lua "$TAR_DIR/plugins/"
+
 tar -C "$DIST" -czf "$DIST/llmsproxy-$VERSION-linux-amd64.tar.gz" \
   "$(basename "$TAR_DIR")"
 rm -rf "$TAR_DIR"
@@ -90,6 +105,45 @@ for f in "$DIST"/llmsproxy_*.deb "$DIST"/llmsproxy-*.rpm "$DIST"/*.tar.gz; do
   [ "$sz" -gt 100000 ] || { echo "[core-dist] FATAL: $f suspiciously small ($sz B)"; exit 1; }
   log "  ✓ $f ($((sz/1024)) KB)"
 done
-dpkg-deb -I "$DIST"/llmsproxy_*.deb 2>/dev/null | grep -E 'Package|Version' | head -2
+# dpkg-deb takes ONE archive; every extra argument is read as an additional
+# control-component name. With the glob unquoted this used to expand to three
+# .deb files (1.5.9 / 1.6.0 / the one just built) and dpkg-deb exited 2 — under
+# `set -e` that aborted the script right here, so the "done" line never printed
+# and NO content verification below ever ran. The size gate above was the only
+# check that ever executed. Pick the newest deb explicitly.
+newest_deb=$(ls -t "$DIST"/llmsproxy_*.deb 2>/dev/null | head -1 || true)
+if [ -n "$newest_deb" ]; then
+  dpkg-deb -I "$newest_deb" 2>/dev/null | grep -E 'Package|Version' | head -2 || true
+fi
+
+# 6) the archive must actually carry what the release notes promise.
+#
+# A size floor alone cannot catch this: a tar.gz missing all 70KB of plugins
+# still clears the 100KB threshold easily, and the seeded-on-first-boot
+# behaviour hides it at runtime — the operator sees a working billing plugin and
+# concludes the package is complete. Assert the file is in the archive.
+log "verifying archive contents..."
+TARBALL="$DIST/llmsproxy-$VERSION-linux-amd64.tar.gz"
+[ -f "$TARBALL" ] || { echo "[core-dist] FATAL: $TARBALL missing"; exit 1; }
+listing=$(tar tzf "$TARBALL" 2>/dev/null || true)
+[ -n "$listing" ] || { echo "[core-dist] FATAL: cannot list $TARBALL"; exit 1; }
+for want in llmsproxy config.example.yaml llmsproxy.service plugins/billing.lua; do
+  if ! printf '%s\n' "$listing" | grep -q "/$want\$"; then
+    echo "[core-dist] FATAL: archive is missing $want"
+    echo "            (release notes claim the billing plugin ships with the core)"
+    exit 1
+  fi
+  log "  ✓ archive contains $want"
+done
+# Directories are matched by their CONTENTS, not by name: tar written with
+# `tar -czf` from a populated tree lists "…/adapters/openai.lua" and never a bare
+# "…/adapters" entry, so an earlier version of this check that grepped for
+# "/adapters$" reported a complete archive as broken.
+n_adapters=$(printf '%s\n' "$listing" | grep -c "/adapters/.*\.lua\$" || true)
+if [ "$n_adapters" -lt 10 ]; then
+  echo "[core-dist] FATAL: archive has only $n_adapters adapters (expected >= 10)"
+  exit 1
+fi
+log "  ✓ archive contains $n_adapters adapters"
 
 log "done: $DIST"