Fix remaining code-review findings (15 bugs; #11 skipped as AID-compatible)

Backend:
- provider: fall back to parsing a plain JSON body when a server ignores
  stream=true (was: silent empty turn); error if response has no text (#5)
- memorybank: clamp cursors after undo/retry shrinks the action list, and
  translate summary_cursor (list position) to an Action.index boundary
  before comparing with Memory.source_end (#7)
- memorybank: pinned memories now count toward the top_k budget (#8)
- memorybank: cosine() returns 0.0 on dimension mismatch; changing the
  embedding model clears stored vectors so they re-embed (#9)
- scripting: MAX_STORY_CARDS cap now counts cards inserted during the
  hook, so a script can't add unbounded cards in one turn (#10)
- settings: /test tolerates non-dict JSON from /models (#13)
- scenarios: import accepts worldInformation as a story-card source (#14)

Frontend:
- per-key debounce timers in PlotPanel and ScenarioEditor — editing two
  things within 600ms no longer drops the first save (#15, #16)
- Continue button no longer discards typed input (#17)
- failed retry resyncs actions from the server instead of leaving the
  removed action missing (#18)
- Settings save/test surface errors instead of hanging on Testing… (#19)
- InsightsPanel ignores stale responses from superseded requests (#20)
- placeholder scan includes story-card trigger keys (#21)

addStoryCard returning the 0-based index (falsy for the first card) matches
real AI Dungeon per the scripting guidebook — kept, documented (#11).
Statuses updated in CODE_REVIEW_FINDINGS.md; stale entries for previously
fixed items (#1-4, #6, #12) corrected.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KFsGHju9szibJJa2YJcdbg

backend/app/routers/scenarios.py

@@ -130,7 +130,13 @@ def import_scenario(bundle: dict = Body(...), db: Session = Depends(get_db)):
     db.add(scenario)
     db.flush()
 
-    cards = bundle.get("storyCards") or bundle.get("worldInfo") or []
+    # AI Dungeon exports have used all three names for the same list.
+    cards = (
+        bundle.get("storyCards")
+        or bundle.get("worldInfo")
+        or bundle.get("worldInformation")
+        or []
+    )
     for card in cards:
         if not isinstance(card, dict):
             continue

backend/app/routers/settings.py

@@ -25,8 +25,17 @@ def read_settings(db: Session = Depends(get_db)):
 @router.put("", response_model=schemas.SettingsOut)
 def update_settings(payload: schemas.SettingsUpdate, db: Session = Depends(get_db)):
     settings = get_settings(db)
-    for field, value in payload.model_dump(exclude_unset=True).items():
+    fields = payload.model_dump(exclude_unset=True)
+    embedding_model_changed = (
+        "embedding_model" in fields
+        and fields["embedding_model"] != settings.embedding_model
+    )
+    for field, value in fields.items():
         setattr(settings, field, value)
+    if embedding_model_changed:
+        # Vectors from the old model have a different dimensionality/space;
+        # clear them so the post-turn task re-embeds with the new model.
+        db.query(models.Memory).update({"embedding": None})
     db.commit()
     return settings
 
@@ -52,6 +61,6 @@ async def test_connection(db: Session = Depends(get_db)):
     try:
         data = resp.json()
         models_available = [m.get("id", "?") for m in data.get("data", [])]
-    except ValueError:
-        pass
+    except (ValueError, AttributeError, TypeError):
+        pass  # non-JSON or unexpected shape — connectivity is still confirmed
     return {"ok": True, "models": models_available}