Add knowledgebases

Knowledgebases give bots RAG over documents, scoped like extensions: to
particular bots, to a workspace, or to every bot, with their own button
beside Tools in the composer. Documents are chunked and embedded by the
file-ingest worker with the install's embedding model, which is now an
install-wide setting rather than a per-bot one.

- Word search runs on an FTS5 index ranked by BM25, with a scored LIKE
  fallback for scripts written without spaces.
- Changing the embedding model re-indexes documents automatically.
- Ingest jobs wait without spending attempts while every embedding model
  rests, fail at once on errors retrying can't fix, and keep passages
  searchable by words when the model refuses.
- Settings > Knowledgebases shows each knowledgebase's and document's
  index state: spinner, warning, grey check (words only) or green check.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/pages/admin/bots/[bot_id]/(partials)/composer-tool-row.tsx

@@ -5,6 +5,7 @@ import Stack from "@moduletrace/twui/layout/Stack";
 import { X } from "lucide-react";
 import extensionIcon from "@/src/components/general/extension-icon";
 import type { BotExtension } from "@/src/types";
+import extensionStateNote from "@/src/utils/extension-state-note";
 
 type Props = {
     item: BotExtension;
@@ -17,24 +18,16 @@ type Props = {
 };
 
 /**
- * One MCP server, tool or skill the bot can use here, in the composer's
- * tools modal. One that isn't working says so, one that's off is struck
- * out. A skill has nothing to connect or run, so it never reports one.
+ * One MCP server, tool, skill or knowledgebase the bot can use here, in
+ * the composer's modals. One that isn't working says so
+ * (`extensionStateNote`), one that's off is struck out.
  */
 export default function ComposerToolRow({ item, busy, onRemove }: Props) {
     const Icon = extensionIcon({ kind: item.kind });
     const notes = [
         item.detail,
         item.source == "workspace" ? "From this workspace" : "",
-        !item.enabled
-            ? "Off for every bot"
-            : item.kind == "skill"
-              ? ""
-              : item.state == "error"
-                ? "Not working"
-                : item.state == "untested"
-                  ? "Not checked yet"
-                  : "",
+        extensionStateNote({ item }),
     ].filter(Boolean);
 
     return (