Bound donor capacity in plan_zone_ratio_retry by min(static_slack,
max(0, clientHeight-scrollHeight)) when both Step 14 measured fields
are present; fall back to static contract slack when absent. Prevents
the donor from being over-allocated when full-but-not-overflowing,
avoiding a wasted Selenium rerender before cascade falls to
cross_zone_redistribute.
- src/phase_z2_retry.py: planner block L122-157 only; donor filter
(L107-112), slack<=0 gate, base_plan, greedy aggregation untouched.
Adds measured_empty_px + slack_bound_source telemetry to
donor_candidates_considered (additive only).
- tests/phase_z2/test_phase_z2_retry_measured_bound.py: 5-axis
regression (static_fallback / measured<static / measured>=static /
measured==0 excludes / filter+bool guard).
Guardrails honored: V4 rank-1 frame lock preserved, no frame_swap,
no spacing/padding/gap/line-height/font shrink, no content drop,
no MDX 03/04/05 branching, no Step 14 schema mutation. Static
fallback idempotent when measured fields absent.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
kyeongmin
dceb10129f