Adds the fast path's volume-based share cap to the live auto path: cap shares to
liquidity_max_volume_pct * cum_volume so a thin cheap name can't be oversized
into heavy slippage (the VTAK-style stop that filled far past its level on
2026-06-23). Threads cum_volume through the setup dict + ready-signal snapshot;
applies max_shares in request_approvals_for_ready_signals, gated by
TRADING_UNIFIED_ENTRY. Fail-open: no cum_volume -> no cap. Protective only
(can only shrink a position).
Tests: thin name capped to liq*cum_volume when on, risk-sized when off. 67 path
tests green. Remaining staged (supervised): the full single _place_entry
chokepoint + fill-model unification + halt-status plumbing.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
