room auto-BYE: free seats lapsed past the renewal grace (2× renewal_period) → RENEWAL_DUE gamer-needed stub — TDD

Phase 5 of the room GATE VIEW + seat-renewal sprint. A seated gamer who
never renews is evicted once their seat's cost passes the renewal-grace
window (filled_at + 2*renewal_period; 14d at the 7d default).

- _expire_lapsed_seats(room): mirrors _expire_reserved_slots — for each
  FILLED slot past 2S, blanks the GateSlot, blanks the matching TableSeat
  (keeps the row for seat-count integrity), records SLOT_RETURNED +
  retracts the prior SLOT_FILLED (scroll redact-pair symmetry), then
  flags the room RENEWAL_DUE. NULL filled_at is never expired (RESERVED
  holds / ORM fixtures / auto-admit trinkets) — protects every existing
  FILLED-slot test
- lazy call sites: room_view, gatekeeper, room_gate (on access; mirrors
  the my-sea delete_stale pattern — no scheduler needed for active rooms)
- room.html: RENEWAL_DUE renders a minimal #id_gamer_needed stub
  (_table_positions + _gatekeeper already suppressed for RENEWAL_DUE).
  Mid-game re-seat flow is a documented follow-on

Tests: ExpireLapsedSeatsTest (10) — frees slot + blanks seat past grace;
no-op within cost window / grace / for null filled_at; sets RENEWAL_DUE;
records SLOT_RETURNED; lazy expiry on room_view + room_gate access;
gamer-needed stub renders. 848 epic+gameboard ITs green.

Code architected by Disco DeDisco <discodedisco@outlook.com>
Git commit message Co-Authored-By:
Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/templates/apps/gameboard/room.html

@@ -109,6 +109,16 @@
             {% include "apps/gameboard/_partials/_sea_overlay.html" %}
         {% endif %}
 
+        {# Gamer-needed stub — a seat lapsed past its renewal grace and was   #}
+        {# auto-BYE'd, so the table no longer fills all six. Minimal stub      #}
+        {# until the mid-game re-seat flow lands (_table_positions +          #}
+        {# _gatekeeper are already suppressed for RENEWAL_DUE below).          #}
+        {% if room.gate_status == "RENEWAL_DUE" %}
+            <div id="id_gamer_needed" class="hex-stub">
+                <p>A seat opened — awaiting a gamer.</p>
+            </div>
+        {% endif %}
+
         {% if room.gate_status != "RENEWAL_DUE" and room.table_status != "SIG_SELECT" %}
             {% include "apps/gameboard/_partials/_table_positions.html" %}
         {% endif %}