Report the world-state changes the engine refuses

`apply_delta` records three outcomes for every change the model sends:
`applied`, `clamped`, and `rejected`. Everything downstream read only
`applied`. A refused change reached the player as an ordinary chip, and
reached the model on the next turn as a change that had succeeded.

Five parts:

- `Action.world_changes` reads `clamped` and `rejected` beside `applied`.
  Accepted stats carry a `clamped` flag; refusals become `kind: "rejected"`
  entries. The `fix` key is present only when the engine wrote one, because
  this property runs for every action of every list response.
- The UI separates the three outcomes. A clamp to a standstill reads
  `no change - at its limit` on a dashed chip, a partial clamp is marked
  `(limited)`, and a rejection carries its reason. Dashed and dimmed rather
  than red: a refused change means the rules are working.
- The goals line names the milestone id, as `milestones.<id>`. The ids
  appeared nowhere in the prompt before, so the model could not send one.
- Each rejection, and each clamp that moved nothing, builds a `fix` string
  from the stat definition at the point of refusal. `render_refusals()`
  renders them into the next prompt above `EMIT_REMINDER`.
- `_history_text` replays `applied_delta()` instead of the sent delta, so a
  past turn's state block shows only what the engine accepted.

A clamp that reduced a change but still moved the value reports nothing. If
you tell a model its 80 damage became 30, it can treat the shortfall as a
debt and send the remaining 50 next turn, which is the swing
`max_delta_per_turn` prevents.

In the demo scenario, `pokemon_left` becomes `pokemon_fainted`
(`type: counter`, `initial: 0`). Starting at the ceiling turned a wrong-signed
delta into a silent no-op; counting up puts the wrong sign on the counter
rule, which refuses it out loud. The instructions also now ask for
`world.turn`, which sat at 0 for a whole playtest.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PacdRuPXSkQQy4ZYdH32hF

backend/app/worldstate/__init__.py

@@ -7,6 +7,7 @@ them against a scenario's `stat_schema`.
 from .engine import (
     EMIT_REMINDER,
     EMIT_RULE,
+    applied_delta,
     apply_delta,
     apply_override,
     band_label,
@@ -16,14 +17,17 @@ from .engine import (
     npc_name,
     npc_triggers,
     reconcile,
+    refusals,
     render_delta_block,
     render_reference,
+    render_refusals,
     render_state_section,
 )
 
 __all__ = [
     "EMIT_REMINDER",
     "EMIT_RULE",
+    "applied_delta",
     "apply_delta",
     "apply_override",
     "band_label",
@@ -33,7 +37,9 @@ __all__ = [
     "npc_name",
     "npc_triggers",
     "reconcile",
+    "refusals",
     "render_delta_block",
     "render_reference",
+    "render_refusals",
     "render_state_section",
 ]