1. cache: record diagnostic miss before early-return on modified()/duration_since() failure
2. dump-state: resolve all cache_dir template vars ({cache_version}, {config_hash})
3. config: remove dead breakpoint_hysteresis field from GlobalConfig (breakpoints.hysteresis is used)
4. config: align Rust Default cache_dir with defaults.json template
5. vcs: apply branch truncation in render_stale_cache (--no-shell path)
6. vcs: fix jj prefetch retry on already-failed command (flatten→unwrap_or_else)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>