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>

src/lembas/main.py

@@ -18,6 +18,7 @@ from lembas.api import (
     admin_audio,
     admin_branding,
     admin_crowd,
+    admin_data_groups,
     admin_extraction,
     admin_images,
     admin_models,
@@ -84,6 +85,7 @@ async def lifespan(app: FastAPI) -> AsyncIterator[None]:
     try:
         from lembas.db.session import session_scope
         from lembas.services.chat import sweep_temporary
+        from lembas.services.data_groups import sweep_unassigned
         from lembas.services.files import sweep_orphans
         from lembas.services.library.documents import sweep_unfiled
         from lembas.services.library.indexing import sweep_orphans as sweep_chunks
@@ -94,6 +96,9 @@ async def lifespan(app: FastAPI) -> AsyncIterator[None]:
             # Documents that predate knowledge bases have nowhere to live until
             # this runs; see services/library/documents.py.
             sweep_unfiled(db)
+            # Rows written before data groups existed, into the group they were
+            # read in -- see services/data_groups.py.
+            sweep_unassigned(db)
             # Temporary chats older than a day. Startup only, like the sweeps
             # above it -- see services/chat.py:sweep_temporary.
             sweep_temporary(db)
@@ -225,6 +230,7 @@ def create_app() -> FastAPI:
     app.include_router(admin_tools.router)
     app.include_router(admin_agents.router)
     app.include_router(admin_crowd.router)
+    app.include_router(admin_data_groups.router)
     app.include_router(push.router)
     app.include_router(branding.router)