classifyHandoffIfNeeded is not defined when subagent completes

Description

Subagents fail with classifyHandoffIfNeeded is not defined after completing their work. The agent's actual output (file writes, analysis) completes successfully, but the teardown/handoff step crashes.

Reproduction

• Version: 2.1.32
• Model: sonnet-4-5-20250929[1m] (also reproduces with opus)
• Trigger: Any Task tool subagent completion
• Example agent name: "Opus 4.6 review - Contracts audit"

Behavior

• Agent completes all work (output files exist and are correct)
• Agent reports as "failed" due to this error
• Error occurs on the handoff step back to parent, not during execution

Impact

Cosmetic but confusing - agents appear to fail when they actually succeeded. Requires manual verification of output files.

Environment

• macOS Darwin 25.2.0
• Claude Code 2.1.32
• MCP servers: claude-in-chrome