"Unhandled node type: pipeline" in permission prompt

Bug

The permission prompt shows Unhandled node type: pipeline when a bash command combines a heredoc with a pipe to a command that has an environment variable prefix.

Repro

Any bash command matching this pattern:

cat <<'EOF' | FOO=bar wc -l
hello
EOF

The permission prompt renders as:

 Bash command

   cat <<'EOF' | FOO=bar wc -l
   hello
   EOF
   Reproduce heredoc pipe with env var prefix

 Unhandled node type: pipeline

 Do you want to proceed?

Simple pipes (cmd1 | cmd2) do not trigger this. The combination of heredoc + pipe + env var assignment on the right-hand side is required.

Root cause

The static bash analyzer uses tree-sitter to walk the AST. The fallback handler Fz returns "Unhandled node type: ${H.type}" for node types not covered by the switch/case dispatchers. pipeline is handled at the top level (it's in the Sq1 set), but in this specific nesting context it reaches the fallback.

Environment

• Claude Code 2.1.105
• macOS (Darwin 25.4.0)