Add a hard trigger for world-state summarization

update_world_state relied entirely on the DM remembering to call it —
no code checked whether it actually happened. Add refresh_if_due(),
called at the top of every DM turn: it counts messages since the
summary was last touched (by the tool or a prior auto-refresh), and
once AUTO_REFRESH_MESSAGE_THRESHOLD (10) is crossed, forces a
dedicated summarization call — a separate, tool-free completion whose
only job is to fold the new messages into the existing summary — and
persists the result directly, without waiting on the main DM turn's
discretion.

The trigger condition (message count) is deterministic; only the
summary text itself still needs an LLM, which is unavoidable for a
task that requires understanding, not just counting.

context.py gained count_messages_since() and build_transcript_text()
(an uncapped, since-filtered plain-text transcript for the
summarizer, as opposed to build_context()'s char-budget-capped chat
list for the main DM call) — factored out of the same underlying
message-labeling logic to avoid duplicating the name-resolution joins.

Verified with a fake LLM client: confirmed the trigger fires exactly
at the threshold and not before, resets after firing, and that the
second refresh's prompt carries the prior summary forward while only
including messages since that refresh (not the whole history again).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/app/llm/orchestrator.py

@@ -88,11 +88,12 @@ async def run_dm_turn(
             f"Name: {game.name}\nBeschreibung: {game.description}"
         )
 
+    await world_state.refresh_if_due(session, game_id, client, settings.dm_model)
     world_summary = await world_state.get_summary(session, game_id)
     if world_summary:
         system_prompt = (
-            f"{system_prompt}\n\nBisheriger Weltzustand (von dir zuletzt über update_world_state "
-            f"zusammengefasst — der Chatverlauf unten zeigt nur ein aktuelles Fenster, das hier "
+            f"{system_prompt}\n\nBisheriger Weltzustand (automatisch/von dir über update_world_state "
+            f"aktuell gehalten — der Chatverlauf unten zeigt nur ein aktuelles Fenster, das hier "
             f"trägt alles Ältere):\n{world_summary}"
         )