Keep searchable text only in knowledgebases

Every bot file was chunked into bot_file_chunks and embedded into
bot_file_vectors, and uploads kept their extracted text in
media.text_content, which together took most of the database. Bot
files are no longer indexed: bots find them by name or path with
list_files and read them with read_file, and search_files, ingest_file
and the files modal's re-read button are gone. Attachments keep no
text; a reply reads a document from the file. Only knowledgebase
documents keep text.

The schema drops both tables and the ingest columns. At boot,
dropStoredFileText removes what older versions stored (file jobs,
upload text) and vacuums once much of the database is free. The
media:prune-text script it replaces is removed.

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

src/data/app-data.ts

@@ -661,8 +661,9 @@ export const AppData = {
      */
     BotFileImportMaxBytes: 20 * 1024 * 1024,
     /**
-     * Ingesting a bot file: how much text one chunk holds, how much of the
-     * previous chunk it repeats, and the largest file it reads at all.
+     * Ingesting a knowledgebase document: how much text one chunk holds,
+     * how much of the previous chunk it repeats, and the largest file it
+     * reads at all (also the largest attachment a reply reads).
      */
     ChunkTargetChars: 1200,
     ChunkOverlapChars: 200,
@@ -681,12 +682,19 @@ export const AppData = {
     EmbeddingBatchSize: 32,
     EmbeddingMaxInputChars: 8000,
     /**
-     * How many chunks a file search returns, and how many more it asks
-     * the vector index for before filtering to the run's scopes.
+     * How many chunks a knowledgebase search returns, and how many more it
+     * asks the vector index for before filtering to the run's ones.
      */
     RagTopChunks: 8,
     RagOverFetch: 4,
     RagMaxK: 60,
+    /**
+     * The database is vacuumed at boot once this share of its pages, and
+     * at least this many bytes, sit free (after a big delete, such as the
+     * bot file index being dropped).
+     */
+    DbVacuumMinFreeRatio: 0.2,
+    DbVacuumMinFreeBytes: 4 * 1024 * 1024,
     /**
      * Knowledgebases: the most one document holds (an upload, or text
      * written in), how much of a pasted text a form takes, how many