Simplify D&D scene chunking responses

internal/modules/dnd/chunk/scenes/assets/prompts/instructions.md

@@ -1,52 +1,8 @@
-Good reasons to start a new scene include:
-- the party moves to a new location;
-- a combat encounter begins or ends;
-- combat changes into a substantially different phase;
-- the party shifts between combat, exploration, social interaction, discussion,
-  planning, travel, rest, or downtime;
-- a new NPC, faction, threat, or objective becomes central;
-- the party completes one immediate goal and begins another;
-- a major table-level rules discussion interrupts and materially changes play.
+Cover the complete provided transcript from its first source unit to its last
+source unit. Return scenes in source-unit order with no gaps or overlaps. Use
+only positive integer source-unit IDs from the transcript, and give every scene
+one inclusive `start_unit_id` and one inclusive `end_unit_id`.
 
-Do not start a new scene merely because:
-- the speaker changes;
-- a new combat round begins;
-- a player asks a brief rules question;
-- there is a joke, aside, or short table comment;
-- a character takes a routine turn;
-- the same encounter continues without a meaningful change in situation.
-
-dnd/scenes boundary policy:
-- cover the full provided transcript from the first source unit to the last
-  source unit;
-- return sequential scenes with no gaps;
-- do not overlap scenes;
-- preserve source-unit order;
-- use integer source-unit IDs from the transcript;
-- each scene must have start_unit_id and end_unit_id;
-- do not include final chunk IDs or chunk indexes.
-
-For each scene:
-- short_title should be brief and factual;
-- primary_mode must be Recap, Discussion, Combat, or Narrative;
-- main_participants should include only principal characters, NPCs, factions, or
-  groups involved;
-- summary should be factual and compact, usually one to three sentences;
-- boundary_note should explain why the scene begins at start_unit_id and ends at
-  end_unit_id;
-- boundary_confidence must be High, Medium, or Low.
-
-Primary mode guidance:
-- Use Recap for opening recap, initiative setup, session framing, or immediate
-  continuation from prior events.
-- Use Discussion when the party is primarily discussing options or choosing a
-  course of action.
-- Use Combat when active combat or combat-resolution mechanics dominate.
-- Use Narrative for all other non-combat gameplay, including exploration, social
-  interactions, shopping, preparation, travel, rest, and downtime.
-
-In boundary_caveats, list overall caveats about scene divisions. Include scenes
-that could reasonably be split differently, combat phases that were kept
-together, gradual transitions, or places where map context would have helped.
-
-Return exactly one JSON object and no explanatory text.
+Return exactly one JSON object and no explanatory text. The object must contain
+only a non-empty `scenes` array. Each scene object must contain only
+`start_unit_id` and `end_unit_id`.