Answer the review, and keep the opening node's bank

Nine findings from a review of the phase-14 stack. The one about a retry
withdrawing a memory is not a bug — a memory anchored to a node describes that
node, and it goes when the node goes. The root is the exception, and it is the
only one: migration 62 parked every memory written before memories had
coordinates on depth 0, so withdrawing the opening node would retire a whole
bank nobody attached there. A memory with no source range covers no story and
now stays; a summary that genuinely ends there is still withdrawn.

The rest are repairs.

* The adventure list quoted whichever attempt was written last rather than the
  one the story tells, so switching back left the index disagreeing with the
  page.
* A v1 import gave a typed memory no depth, rebuilding the NULL the migration
  exists to remove — invisible until the imported adventure forked.
* The action cap counted a v1 file's turns, and a turn expands into a row per
  saved attempt, so a file inside the cap could write a multiple of it.
* Forking a live node on a borrowed ancestor promoted a sibling on a branch the
  caller never named. It is a branch switch, and now says so.
* Switching attempts left the state, status and memory panels reading the
  previous take: the story does not change length, so nothing keyed on its
  length noticed. Same class as the branch-switch bug this phase already fixed.
* A retry after switching back numbered the new attempt into the middle of the
  group instead of the end.
* The cursor backfill numbered every action in the table once per adventure;
  correlated to the adventure being updated, it is an index lookup instead.
* Renaming a branch answered own_actions=0.

And one behaviour change recorded rather than repaired: script-visible history
and actionCount no longer count blank-text rows. That is the right shape and
there is no reading compatible with both, so plan/14 says so.

409 tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015H5qiyiR7gtFQaoDphHZ3g

backend/tests/test_bundle_v2.py

@@ -533,6 +533,75 @@ def test_a_v2_bundle_brings_its_anchors_back(client):
         db.close()
 
 
+def test_a_v1_memory_that_summarises_nothing_lands_on_the_root(client):
+    """The import has to answer the question migration 62 answered.
+
+    A v1 file has no depths, and a memory the player typed has no `sourceEnd`
+    to derive one from — so it used to come back with a NULL depth, which is the
+    exact state SP7 removed from the schema. `Path._entry_clause` compares
+    `depth <= max_depth` and a NULL fails it, so the memory would read fine
+    until the imported adventure was forked and then vanish from the new branch.
+    """
+    payload = {
+        "format": bundle.LEGACY_FORMAT, "title": "Old backup",
+        "memoryCursor": 0, "summaryCursor": 0,
+        "actions": [
+            {"index": 0, "type": "start", "text": OPENING},
+            {"index": 1, "type": "story", "text": "A corridor."},
+        ],
+        "memories": [
+            {"text": "Kira is the innkeeper's daughter"},          # typed
+            {"text": "The corridor, summarised", "sourceStart": 1, "sourceEnd": 1},
+        ],
+    }
+    copy = _imported(client, payload)
+
+    db = SessionLocal()
+    try:
+        rows = {m.text: m for m in db.query(models.Memory)
+                .filter(models.Memory.adventure_id == copy).all()}
+        assert rows["Kira is the innkeeper's daughter"].depth == 0, (
+            "a typed memory anchors at the root, which every branch can see"
+        )
+        assert rows["The corridor, summarised"].depth == 1, "derived from its range"
+        assert all(m.depth is not None for m in rows.values())
+        assert all(m.branch_id is not None for m in rows.values())
+    finally:
+        db.close()
+
+
+def test_the_action_cap_counts_the_rows_a_v1_file_expands_into(client, monkeypatch):
+    """The cap has to count what gets written, not what the file lists.
+
+    A v1 turn carries its retries in a `variants` array, and SP4 made every
+    attempt a row — so one entry can become ten. Counting entries lets a file
+    inside the cap write a multiple of it, and the body limit is no help: the
+    text is tiny, it is the row count that is the cost.
+    """
+    monkeypatch.setattr(auth, "MULTI_USER", True)
+    monkeypatch.setattr(limits, "MAX_ACTIONS_PER_ADVENTURE", 6)
+    monkeypatch.setattr(limits, "_BUNDLE_LIST_CAPS",
+                        {**limits._BUNDLE_LIST_CAPS, "actions": 6})
+    payload = {
+        "format": bundle.LEGACY_FORMAT, "title": "Small file, many rows",
+        "memoryCursor": 0, "summaryCursor": 0,
+        "actions": [{"index": 0, "type": "start", "text": OPENING}] + [
+            {
+                "index": i, "type": "ai", "text": "Take four.",
+                "variants": [{"text": f"Take {n}."} for n in range(4)],
+                "variantIndex": 3,
+            }
+            for i in range(1, 4)
+        ],
+    }
+    assert len(payload["actions"]) <= 6, "the file itself is inside the cap"
+    before = _adventure_count()
+
+    r = _import(client, payload)
+    assert r.status_code == 409, r.text
+    assert _adventure_count() == before, "and nothing was written"
+
+
 def test_an_unknown_format_is_refused(client):
     r = _import(client, {"format": "ai-dnd-adventure-v3", "title": "From the future"})
     assert r.status_code == 400, r.text