Data groups: a provider's models read only their own group's data

Every connection is in a data group. Its models are handed, and can find,
only that group's memories, notes, skills, knowledge, reports and
personality -- by search and by id. A chat stays in the group it was
started in: switching its model, the endpoint fallback, the crowd, friends,
bases and the @ menu all stay inside it, and a chat whose model has moved
is refused rather than sent. A group may name its own embedder and image
reviewer. data.manage lets a person make personal groups, remap
connections for themselves and move their own records.

Also: a search no longer mixes two embedders of the same width.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/shoot.py

@@ -261,6 +261,10 @@ def authored_sideways() -> tuple[str, ...]:
     return tuple(selectors)
 
 
+# The chat `build_client` seeds, so a run can name `/chat/<SHOOT_CHAT>`.
+SHOOT_CHAT = "5" * 32
+
+
 def build_client():
     import lembas.config as config_mod
 
@@ -293,6 +297,45 @@ def build_client():
         for name in ("gemma4-moe", "qwen3-coder"):
             db.add(Model(connection_id=connection.id, model_id=name, display_name=name))
 
+    # A second data group with a hosted model in it, a note in each group and a
+    # chat with a fixed id (`SHOOT_CHAT`). Without them every grouped screen --
+    # the chips, the Data tab, the models named under the picker as being in
+    # another group -- is rendered with nothing in it, which is the "a screen the
+    # test never renders is unchecked" lesson again.
+    from lembas.db.models import Chat, DataGroup, Note, User
+
+    with session_scope() as db:
+        db.add(DataGroup(id="hosted", name="Hosted providers"))
+        hosted = Connection(
+            name="hosted",
+            base_url="http://127.0.0.1:2",
+            api_key_encrypted="",
+            data_group_id="hosted",
+        )
+        db.add(hosted)
+        db.flush()
+        db.add(
+            Model(
+                connection_id=hosted.id,
+                model_id="deepseek-flash",
+                display_name="DeepSeek Flash",
+            )
+        )
+        owner = db.query(User).first()
+        db.add(Note(owner_id=owner.id, title="A note at home", body="x", data_group_id="default"))
+        db.add(Note(owner_id=owner.id, title="A hosted note", body="x", data_group_id="hosted"))
+        local = db.query(Connection).filter_by(name="local").first()
+        db.add(
+            Chat(
+                id=SHOOT_CHAT,
+                user_id=owner.id,
+                model_id="gemma4-moe",
+                connection_id=local.id,
+                data_group_id="default",
+                title="A chat to measure",
+            )
+        )
+
     # 🚨 The suggestion cards are seeded by the startup hook, and `TestClient(app)`
     # runs a lifespan only inside a `with` block -- so every shot of the new-chat
     # screen ever taken by this script was of a page with its cards missing. That