Let players roll their own physical dice instead of the DM

Adds the "Ich würfle selbst" checkbox the user asked for, plus the
structural piece that makes it actually reliable: a tool call can't
block mid-turn waiting for a human to go find a d20, so this can't be
a pure client-side toggle — the DM has to think in two turns (ask,
then later recognize the answer), and it's easy for an LLM to lose
track of that across a real gap in the conversation.

game_participants gets self_rolls (the toggle) and pending_roll (what
roll is currently awaited, if any). When self_rolls is on, roll_dice
doesn't touch the RNG — it validates the notation, stores it as
pending_roll, and returns an "awaiting_player_roll" result that tells
the DM to ask for that exact roll and wait, never inventing a number.
At the top of the player's next turn, orchestrator.run_dm_turn reads
back any pending_roll, injects it as an explicit reminder into the
system prompt ("the player's message is probably answering this"),
and clears it — so the DM doesn't have to rely on remembering what it
asked for several messages ago.

Frontend: the checkbox lives in the game header (PATCH
/api/games/{id}/self-rolls, per-participant). A persistent "🎲 Du bist
am Zug" banner shows the pending notation/reason — persistent, not
transient like the typing/rolling indicators, since answering it means
physically finding a die and rolling, which takes real time. It's
seeded from GameRead.my_pending_roll on load so it survives a page
reload, and only clears when the player actually sends their next
message (not when the DM's message arrives, which would make it
disappear before there was time to read it).

Verified live end-to-end against x.ai in a real session: toggled the
setting, asked for something requiring a check, got "würfle bitte
1d20+1" instead of an auto-rolled result, confirmed the banner
survived a full page reload, replied "14", and the DM used that
number directly ("Du hast 14 gewürfelt — das reicht") without
re-rolling — with pending_roll correctly cleared in the DB afterward.
Also confirmed per-participant scoping (a second participant's flag
stayed off) and that toggling back off works cleanly.

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

backend/app/llm/orchestrator.py

@@ -54,6 +54,34 @@ async def _execute_tool_call(
         return {"error": str(exc)}
 
 
+async def _request_player_roll(
+    session: AsyncSession, participant: GameParticipant, notation: str, reason: str
+) -> dict:
+    """Handles a roll_dice call for a player who rolls their own physical dice: validates the
+    notation without touching the RNG, records it as the participant's pending roll (picked up
+    and cleared at the top of their next turn), and returns a tool result that tells the DM to
+    ask for it and wait instead of rolling itself."""
+    try:
+        dice.parse_notation(notation)
+    except ValueError as exc:
+        return {"error": str(exc)}
+
+    participant.pending_roll = {"notation": notation, "reason": reason}
+    await session.commit()
+
+    return {
+        "awaiting_player_roll": True,
+        "notation": notation,
+        "reason": reason,
+        "note": (
+            f"Der Spieler würfelt selbst mit physischen Würfeln. Nenne ihm klar und knapp, was er "
+            f"würfeln soll ({notation}" + (f", {reason}" if reason else "") + "), und warte auf "
+            "seine Antwort mit dem Ergebnis in einer künftigen Nachricht — würfle nicht selbst und "
+            "erfinde kein Ergebnis."
+        ),
+    }
+
+
 async def _check_hp_game_over(session: AsyncSession, game_id: uuid.UUID, result: dict) -> str | None:
     """After an upsert_character_sheet call, auto-ends the game if the character it touched
     dropped to 0 HP or below. Returns the end reason if the game was just ended, else None."""
@@ -76,12 +104,38 @@ async def run_dm_turn(
     session: AsyncSession,
     game_id: uuid.UUID,
     latest_player_message: str | None = None,
+    user_id: uuid.UUID | None = None,
     on_roll: Callable[[str], Awaitable[None]] | None = None,
+    on_awaiting_roll: Callable[[str, str], Awaitable[None]] | None = None,
     on_game_ended: Callable[[str], Awaitable[None]] | None = None,
 ) -> Message:
     client = get_llm_client()
     system_prompt = get_dm_system_prompt()
 
+    participant: GameParticipant | None = None
+    if user_id is not None:
+        participant = (
+            await session.execute(
+                select(GameParticipant).where(
+                    GameParticipant.game_id == game_id, GameParticipant.user_id == user_id
+                )
+            )
+        ).scalar_one_or_none()
+
+    if participant is not None and participant.pending_roll:
+        pending = participant.pending_roll
+        system_prompt += (
+            f"\n\nOffene Würfelanfrage: Du hast {pending.get('notation')} "
+            f"({pending.get('reason') or 'ohne Angabe'}) angefragt, der Spieler würfelt selbst. "
+            "Seine gerade eingegangene Nachricht enthält vermutlich das Ergebnis dieses Wurfs — "
+            "nimm die genannte Zahl direkt als Wurfergebnis, würfle NICHT selbst und frag nicht "
+            "erneut danach, außer die Nachricht beantwortet die Anfrage erkennbar nicht."
+        )
+        # Consumed either way — if the message didn't actually answer it, the DM asking again
+        # via roll_dice creates a fresh pending_roll for next time.
+        participant.pending_roll = None
+        await session.commit()
+
     game = await session.get(Game, game_id)
     if game is not None:
         system_prompt = (
@@ -145,9 +199,17 @@ async def run_dm_turn(
 
         for tool_call in message.tool_calls:
             tool_input = fix_double_escaped_unicode(json.loads(tool_call.function.arguments))
-            if tool_call.function.name == "roll_dice" and on_roll is not None:
-                await on_roll(tool_input.get("notation", ""))
-            result = await _execute_tool_call(session, game_id, tool_call.function.name, tool_input)
+
+            if tool_call.function.name == "roll_dice" and participant is not None and participant.self_rolls:
+                notation = tool_input.get("notation", "")
+                reason = tool_input.get("reason", "")
+                result = await _request_player_roll(session, participant, notation, reason)
+                if "error" not in result and on_awaiting_roll is not None:
+                    await on_awaiting_roll(notation, reason)
+            else:
+                if tool_call.function.name == "roll_dice" and on_roll is not None:
+                    await on_roll(tool_input.get("notation", ""))
+                result = await _execute_tool_call(session, game_id, tool_call.function.name, tool_input)
 
             end_reason = None
             if tool_call.function.name == "end_game" and "reason" in result: