fix(ci): avoid leaking cache lock to MSBuild nodes [CI]

ci/release-linux.sh

@@ -73,9 +73,11 @@ mkdir -p "$sqlite_cache_root/locks"
 # Stable cache paths let MSBuild reuse the SQLite amalgamation object between
 # fresh Woodpecker workspaces. Lock per RID so overlapping retries cannot write
 # the same object concurrently; amd64 and arm64 builds remain parallel.
+# --close keeps the lock fd out of reusable MSBuild worker processes. Otherwise
+# an idle node-reuse worker can inherit it and block later pipelines indefinitely.
 (
   cd "$root/backend"
-  flock -w 900 "$sqlite_cache_root/locks/$rid.lock" \
+  flock --close --wait 900 "$sqlite_cache_root/locks/$rid.lock" \
     dotnet publish src/MoShiro.Backend \
       -m:8 -c Release -r "$rid" --self-contained true \
       -p:DebugType=none -p:DebugSymbols=false \