[FEATURE] Configurable summary detail level for /compact

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

/compact compresses more than my workflow needs: exact function signatures, diagnosed error messages, and rejected design alternatives are dropped, forcing file re-reads to restore them. Every existing setting (CLAUDE_AUTOCOMPACT_PCT_OVERRIDE, autoCompactWindow; #10691, #42149, #66475) controls when compaction fires — nothing controls how much the summary retains. /compact [instructions] selects topics, not detail level; natural-language verbosity requests are unreliable.

Related but distinct: #72461 (summary format), #78197 (segment priorities), #14258 (CLAUDE.md verbatim retention).

Proposed Solution

/compact --detail=low|medium|high [instructions]

high keeps verbatim code snippets, exact error text, and decision rationale; low matches today. Mirrors the /effort / /code-review <level> UX. Alternatives: --target-tokens=N, or a compactionDetail settings key that also governs auto-compaction.

The optimal retention level is task-dependent — long refactors need fidelity, task switches need aggressive compression — so it should be user-settable rather than fixed.

Alternative Solutions

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Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

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Additional Context

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