fix: post_turn consumes pending meanwhile digests (T82.1)

Wire chat.services.prompt.consume_pending_meanwhile_digests into
chat.web.turns.post_turn at the END of the handler, after scene-close
detection and before the response broadcast. Without this call digests
created by a meanwhile close stay pending forever — they surface in the
next you-turn's prompt (via T65) but are never marked consumed, so they
re-render on every subsequent turn.

Idempotent: re-calling the helper produces zero events when nothing's
pending. The T66 cross-feature note is updated to reflect the new
wiring; the existing direct-helper test in test_phase3_integration.py
is preserved as defensive coverage of the helper contract in isolation.

chat/web/turns.py

@@ -64,7 +64,10 @@ from chat.services.event_promotion import promote_completed_event
 from chat.services.interjection import detect_interjection
 from chat.services.memory_write import record_turn_memory_for_present
 from chat.services.multi_state_update import compute_state_updates_for_present
-from chat.services.prompt import assemble_narrative_prompt
+from chat.services.prompt import (
+    assemble_narrative_prompt,
+    consume_pending_meanwhile_digests,
+)
 from chat.services.rewind import compute_rewind_preview, execute_rewind
 from chat.services.scene_close import detect_scene_close
 from chat.services.scene_summarize import apply_scene_close_summary
@@ -886,6 +889,15 @@ async def post_turn(
                 timeout_s=settings.classifier_timeout_s,
             )
 
+    # 9a. Consume any pending meanwhile digests now that the assistant_turn
+    # (which surfaced them in its prompt via T65's helper) has landed. The
+    # spec's "first you-turn AFTER meanwhile close consumes the digest"
+    # semantics are preserved by running this AFTER scene-close detection
+    # — anything pending right now belongs to the prompt we just answered,
+    # so it's safe to mark consumed and the NEXT turn starts clean.
+    # Idempotent: re-calling produces zero events when nothing's pending.
+    consume_pending_meanwhile_digests(conn, chat_id)
+
     # 10. Broadcast a JSON completion event (for JS consumers) and an HTML
     # fragment event (for HTMX SSE swap-into-timeline). One pair per
     # written assistant_turn so the timeline ends up with both the