context-monitor.sh compact-ladder: window-relative tiers replace host-wide absolute constants

Root cause: NUDGE_AT/COMPACT_AT/QUARANTINE_AT (180k/220k/250k) are host-wide absolute, blind to per-agent CLAUDE_CODE_AUTO_COMPACT_WINDOW. lezama's 4 mba-l agents (coder-mba-l-cc/coder02/db-mba-l/db02, all set to 400000) get false-quarantined at ~220-250k instead of near 400k (17 real fires, ctx 251k-358k, 7 days - v4.75 in-file note). FINAL RULING (2026-08-19/20, monitor-context-cc as actuator-semantics owner, bin-lezama-cc build+verify, bin-venus-cc coordinate+push): ratios nudge=0.70x window, compact=0.85x window, quarantine=0.95x window. Window resolved via settings precedence chain (project settings.local.json -> project settings.json -> ~/.claude/settings.json -> 250000 literal floor; NOT 200000 - zero hosts run a 200k default). No environ shortcut (CLAUDE_CODE_AUTO_COMPACT_WINDOW not in process environ, confirmed via /proc/<pid>/environ). Ship gate: two separately-named assertions - ASSERT-A (nudge <= host's own observed CC-action band, per-host, never pooled) + ASSERT-B (compact/quarantine strictly < 1.0x window, pure arithmetic) - must fail a deliberately-unreachable tier before trusted to pass the real one. Commit must cite the 17-fire figure, NOT retracted venus/tick.py numbers (1915/6262/11968 - wrong host, wrong actuator, wrong population, caught and struck). Backstop semantics from RECENT_BOUNDARY_SEC (:1656-1663) boundary check, not tier height - 'must clear an observed ceiling' proven dead as a design rule (3 hosts, 3 incompatible unsatisfiable geometries). whey's leg: no 400k overrides on host, change is inheriting-population-only 180/220/250->175/212.5/237.5, described separately, NOT riding mba-l justification. STATUS as of session end: spec fully ratified by monitor-context-cc/bin-lezama-cc/bin-venus-cc. bin-lezama-cc had a build (v4.78) with a stale ratio (0.90 not 0.85 for compact, and whey's 225k not 212.5k) that needs the fix applied and gate re-run before push. NEXT: confirm bin-lezama-cc corrected the build, gate demonstrates fail-on-unreachable + pass-on-real, then bin-venus-cc pushes to sh.git. Registry rows 1 (venus, monitor-context-cc) and 37 (lezama, bin-lezama-cc) get stale-note corrections in ONE post-ship pass (wrong '190k' constant, describes retired-on-venus mechanism as live).