ci: add NeoForge JAR collection to GitHub Release step

[turtton]

Summary

• Create GitHub Release ステップの JAR 収集 glob を +fabric-*.jar のみから fabric + neoforge 両対応に拡張
• sources JAR / client-gametest JAR を除外するフィルタを追加
• shell: bash を明示（bash 固有構文 shopt, 配列, [[ ]] 使用のため）

Changes

# Before: fabric only
assets=(versions/*/build/libs/connectedtank-"${MOD_VERSION}"+fabric-*.jar)

# After: fabric + neoforge, with exclusion filters
assets=()
for jar in \
  versions/*/build/libs/connectedtank-"${MOD_VERSION}"+fabric-*.jar \
  versions/*/build/libs/connectedtank-"${MOD_VERSION}"+neoforge-*.jar; do
  [[ "$jar" == *-sources.jar ]] && continue
  [[ "$jar" == *-client-gametest.jar ]] && continue
  [[ "$jar" == *-client-gametest-remapped.jar ]] && continue
  assets+=("$jar")
done