M5: genre-neutral authoritative narrative state, with review corrections

Replaces AI-DnD's RPG relative-delta world state with the genre-neutral typed
narrative state of ADR 010: explicit, absolute, allowlisted events proposed by
the model, validated by the application, applied to one authoritative document,
and snapshotted per position so restore stays a row read.

This commit includes the corrective pass that followed the independent review
in planning/reports/M5-IMPLEMENTATION-REPORT.md. The invariant it exists to
hold is:

    visible active transcript position == stored head == authoritative state

Narrator editing (D10, STORY-BRANCH-SEMANTICS §§14-15)

  A narrator edit no longer rewrites a row. It returns to the state before the
  turn, takes the reader's exact text as the accepted narration, re-derives the
  state that text implies, and becomes a new active continuation — while the
  original narration keeps its words, its live flag and its whole future as
  retained history. At the tip the correction is another take; with story below
  it, it forks. No new history machinery: this is the existing fork/take/head
  path with the reader's text in place of a generated reply. The §14A refusal
  is therefore gone for narrator turns, and remains only for player input.

Pre-M5 positions

  Migration 88 backfills the empty narrative document onto every action written
  before M5, and a missing snapshot now restores the empty document instead of
  leaving the previous position's state standing. Restoring to an old Save
  Point no longer leaves a later position's entities and facts on screen.

Narrator context

  Replayed history carries prose only; the machine-readable block is no longer
  reconstructed into past turns, where it contradicted the authoritative state
  in the same prompt. A fact withdrawn by a manual correction is now named as
  no longer true, with the reader's reason, rather than silently dropped.

Also

  - state_changes joins the action-list bulk read, removing one query per row.
  - Extraction takes only the application's own protocol payload: an ordinary
    ```json or ```python block in a story survives, and a mangled proposal
    still does not reach the reader.

Planning: ADR 013 records the authoritative document shape; §§14-15/14A, D10,
C04 and BUILD-MILESTONES are updated to describe what exists. Debt is recorded
against M8 (scenario editor UX) and M9 (export of the audit trail).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PWU4gTfLYY6Qq9U7aa9Qw2

backend/tests/test_take_state.py

@@ -24,14 +24,17 @@ from app.database import Base, SessionLocal, engine, get_db
 from app.main import app
 from app.routers import adventures
 
-from fakes import GOLD_SCHEMA, ScriptedProvider, gold_replies, gold_reply
+from fakes import (
+    GOLD_SCHEMA, ScriptedProvider, gold_replies, gold_reply, tally_of,
+    tally_reply,
+)
 
 SCHEMA = GOLD_SCHEMA
 
-# Ten gold a turn, every turn, banked through the world-state engine. A number
-# that only ever increases makes a rollback failure obvious: if a take stacks
-# instead of replacing, the gold total is off by exactly one turn's worth. See
-# `fakes.gold_reply` for why this is not a script any more.
+# A running tally, ten a turn, recorded through the narrative-state engine as an
+# absolute total. A take that stacked instead of replacing would show a value no
+# position ever established. See `fakes` for why the instrument is a typed event
+# now rather than a script or a delta.
 
 
 @pytest.fixture()
@@ -47,7 +50,6 @@ def client(monkeypatch):
     setup.flush()
     adv = models.Adventure(
         user_id=user.id, title="Vault", scenario_id=scenario.id,
-        world_state={"player": {"hp": 100, "gold": 0}},
     )
     setup.add(adv)
     setup.flush()
@@ -95,7 +97,7 @@ def _take(client, action_id, text=""):
 def _gold(adv_id) -> int:
     db = SessionLocal()
     try:
-        return (db.get(models.Adventure, adv_id).world_state or {}).get("player", {}).get("gold", 0)
+        return tally_of(db.get(models.Adventure, adv_id).narrative_state)
     finally:
         db.close()
 
@@ -124,18 +126,21 @@ def test_the_script_runs_once_a_turn(client):
 def test_a_take_of_a_past_ai_turn_does_not_stack_its_script(client):
     """Two turns played, then the first one taken again.
 
-    The take leaves the path just before turn one. The state it starts from
-    is the state turn one started from: zero gold, not the twenty that two
-    turns accumulated. The take's own run then adds ten.
+    The take leaves the path just before turn one, so the state it produces is
+    its own — not the value the two-turn line had reached. Under M5 the take
+    states its total absolutely, which is what makes the assertion a fact about
+    *which position is current* rather than about how many times something was
+    added.
     """
     _play(client)
     _play(client, "press on")
     assert _gold(client.adv_id) == 20
 
     first_ai = _rows(client.adv_id, "ai")[0]
+    ScriptedProvider.replies = [tally_reply("Another telling.", 10)]
     _take(client, first_ai.id)
 
-    assert _gold(client.adv_id) == 10, "rolled back to before that turn, then run once"
+    assert _gold(client.adv_id) == 10, "the take's own state, not the line it left"
 
 
 def test_a_take_of_a_player_turn_does_not_stack_its_script(client):
@@ -144,28 +149,33 @@ def test_a_take_of_a_player_turn_does_not_stack_its_script(client):
     assert _gold(client.adv_id) == 20
 
     first_player = _rows(client.adv_id, "do")[0]
+    ScriptedProvider.replies = [tally_reply("A different opening.", 10)]
     _take(client, first_player.id, "> You do something else.")
 
-    assert _gold(client.adv_id) == 10
+    assert _gold(client.adv_id) == 10, "the take's own state, not the line it left"
 
 
 def test_writing_below_a_passed_take_starts_from_that_take_s_state(client):
     """The `after_id` path, which forks while writing.
 
-    The take being written under produced a state of ten gold, from its own
-    turn. The turn played on top of it adds another ten. The twenty gold
-    that the abandoned line reached has no effect on this branch.
+    Writing under a take the story moved past starts from that take's state,
+    not from the state the line that continued had reached. The new turn states
+    its own total, and the value the abandoned line reached must not be what is
+    current afterwards.
     """
     _play(client)
+    ScriptedProvider.replies = [tally_reply("A second telling.", 10)]
     r = client.post(f"/api/adventures/{client.adv_id}/retry")
     assert r.status_code == 200, r.text
+    ScriptedProvider.replies = [tally_reply("Onward.", 20)]
     _play(client, "press on")
     assert _gold(client.adv_id) == 20
 
     discarded = [a for a in _rows(client.adv_id, "ai") if not a.live][0]
+    ScriptedProvider.replies = [tally_reply("A different way.", 55)]
     _play(client, "a different way", after_id=discarded.id)
 
-    assert _gold(client.adv_id) == 20, "that take's ten, plus this turn's ten"
+    assert _gold(client.adv_id) == 55, "this branch's own state"
 
 
 def test_the_line_left_behind_keeps_the_state_it_reached(client):
@@ -173,6 +183,7 @@ def test_the_line_left_behind_keeps_the_state_it_reached(client):
     _play(client)
     _play(client, "press on")
     first_ai = _rows(client.adv_id, "ai")[0]
+    ScriptedProvider.replies = [tally_reply("Another telling.", 10)]
     _take(client, first_ai.id)
     assert _gold(client.adv_id) == 10