docs(db): legacy JSON files are deletable once tables are populated: the on-disk copies of users/history/searches were verified superseded by SQLite and removed; the docstring claimed they were kept as a snapshot

server/db.py

@@ -7,9 +7,9 @@ reconnect cost is zero. WAL: SQLite serializes writers itself, so the
 lost-update races of the JSON read-modify-write era are gone.
 
 One-time import: a table that is empty while its legacy JSON still exists
-gets absorbed (users.json, history/*.json, searches/*.json). The JSON files
-are left in place as a last-known-good snapshot; the empty-table guard makes
-a second import impossible. Legacy ghost rows (same episode stored with int
+gets absorbed (users.json, history/*.json, searches/*.json); the files are
+deletable once the tables are populated (the empty-table guard makes a
+second import impossible). Legacy ghost rows (same episode stored with int
 AND str ep_id) are deduped on import: newest t per (user, slug, ep).
 """
 import json