Add context.Context parameter to all FeedIndex methods that perform SQL queries but previously lacked it, and switch from Query/Exec/QueryRow to their Context variants (QueryContext/ExecContext/QueryRowContext).
This leverages the existing otelsql instrumentation to automatically create spans for ALL SQL operations when there's a parent span from the HTTP middleware — no manual tracing.SqliteSpan() needed per method. The otelsql SpanFilter ensures background operations (firehose consumer) don't create orphan spans since they lack a parent span.
Methods updated: GetCursor, SetCursor, DeleteRecord, GetRecord, GetKnownDIDs, ListRecordsByCollection, BrewCountsByRecipeURI, refCounts, BrewCountsByBeanURI, BrewCountsByGrinderURI, BrewCountsByBrewerURI, BeanCountsByRoasterURI, IsBackfilled, MarkBackfilled, UpsertLike, DeleteLike, GetLikeCount, HasUserLiked, GetUserLikeRKey, UpsertComment, DeleteComment, GetCommentCount.
Also switched existing context-aware methods (UpsertRecord, GetProfile) to use ExecContext/QueryRowContext instead of Exec/QueryRow.