[FEATURE] Post-compact hook lines print the full hook command into context; show statusMessage or truncate

What happens

After every /compact, Claude Code prints one line per PreCompact / PostCompact hook:

PreCompact [<full command>] completed successfully
PostCompact [<full command>] completed successfully: <output>

The bracketed part is the hook's entire command string. The same text is also stored in the transcript as local-command-stdout, so the model reads it as context right after the compaction that was meant to free context.

This gets expensive when the command is long. Orca (stablyai/orca) registers a ~3 KB portable shell wrapper for PostCompact, with Windows Git Bash, PowerShell, missing-HOME and missing-script branches, so every /compact puts about 1k tokens of shell code back into context. Orca is shortening its own command (stablyai/orca#25209, PR #25211), but any tool that installs a long hook command hits the same problem.

Repro

1. Add a PostCompact hook whose command is long (several hundred characters or more).
2. Run /compact.
3. The full command is printed after compaction, and the next turn's context contains it.

Observed on Claude Code 2.1.296, macOS. The display name comes from the function that renders a hook (type === "command" → command, joined with args). It never uses the hook's statusMessage, although statusMessage is already accepted and shown in the spinner while the hook runs.

Request

1. In the post-compact lines, show statusMessage when the hook has one, and otherwise truncate the command (for example to its first ~80 characters plus …).
2. Optionally, leave successful hook lines with empty or {} output out of the model-visible context entirely. They carry no information for the model.

Searched first

I searched anthropics/claude-code issues for "PostCompact", "PreCompact completed successfully", "hook command shown transcript" and "alwaysLoad". The nearest threads are #89622 (PostCompact stdin JSON escaping), #91910 (compact hooks firing for sub-agent compaction) and #101070 (an "idle" trigger value). None covers how the hook is displayed or what it costs in context.