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/help/(data)/help-topics.ts

@@ -119,4 +119,16 @@ A bot's own models (the model icon in its chat header) win over the defaults, an
 
 Tell the bot your time zone once ("I'm in Lagos", "I'm on New York time") and it remembers it and converts for you. To fix one yourself, open **Routines**, click **Edit**, and change the schedule to the UTC hour you want. Routines don't follow daylight saving changes, so ones near a clock change may need a nudge twice a year.`,
     },
+    {
+        id: "knowledgebase-not-found",
+        title: "A bot doesn't use a knowledgebase",
+        summary: "It answers from memory, or says it found nothing, though the document is there.",
+        body: `A super admin makes knowledgebases in **Settings, Knowledgebases**, and a bot searches one only once it's given it: from the knowledgebases button under its composer, its settings page, or a workspace it works in.
+
+If it's given and still misses:
+
+- Open the knowledgebase's documents. A document still **being read** isn't searchable yet; one that **couldn't be read** names why (a scan with no text, a file too big). Write the text in instead, or upload a version with text in it.
+- Bots search by meaning only with an embedding model, picked once for the whole install in **Settings, Models** under Embeddings. Without one they match words, which misses questions worded differently from the document. Picking or changing the model reads every document again on its own; a document shows **needs re-indexing** until it's done.
+- If a document still says it needs re-indexing, use the refresh icon on its knowledgebase's row to read them all again.`,
+    },
 ];