Three new environment variables for progress summaries, sleep-compact timing and the resume hook wait

What

Environment variables are named settings passed to a program when it starts. This release adds three new ones. None of them appeared in the previous build, and each does nothing unless it is set:

• CLAUDE_CODE_AGENT_PROGRESS_SUMMARIES: turns on a progress-summary switch during client setup, but only under a further condition that was not traced. Its entry in the settings-to-environment table is hard-coded to off, near CLAUDE_CODE_QUESTION_OPTIONAL_DESCRIPTIONS.
• CLAUDE_CODE_SLEEP_COMPACT_AFTER_MS: supplies the afterTurnMs value used to time the existing CLAUDE_CODE_SLEEP_COMPACT feature, and only under a further internal check. Setting it also counts as sleep-compact being on, alongside CLAUDE_CODE_SLEEP_COMPACT.
• CLAUDE_CODE_RESUME_SESSIONSTART_HOOKS_WAIT_MS: makes a resumed session wait for SessionStart hooks, which are scripts run when a session begins or resumes. Resume now passes an onOverdueSessionStartHooks callback that receives the output of hooks that have not finished. When they run long, Claude Code reports: "SessionStart hooks are still running after ... ms: waiting until they end, because an administrator's hook may be among them".

All three are on the host-managed lists, so they are removed from the environment of processes Claude Code starts. They have no matching user-facing setting.

Why

These variables let whatever program launches Claude Code tune subagent progress summaries, sleep-compaction timing, and how a resumed session handles slow SessionStart hooks. Because they are stripped from child processes, tools Claude Code runs will not see them.