docs(deployment): validating-metadata.mdx names the driver refusal, not the swallowed empty list

The filter-position passage said the driver's "no such column" is swallowed
and the list comes back empty. driver-sql, and the local faces of
TursoDriver/SqliteWasmDriver (both extend SqlDriver), have refused an
unresolvable WHERE column with INVALID_FILTER / 400, naming the column,
since #8790. The Turso remote face refuses the same way as of 3e8b492
(#20461), through the inherited aggregateBackendFault seam. Rewrote the
passage to the refusal and its remedy (schema sync, or naming a column the
table has), and reworded the "why an error not a warning" rationale to match.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VDtqoecgES7ScQYGbFVDRv

Author: claude

content/docs/deployment/validating-metadata.mdx

@@ -378,11 +378,13 @@ A **filter position** is the exception that gates:
 //                                                                        ↑ error, not a warning
 ```
 
-An unknown column in a predicate is not a skipped column — the predicate can
-never match, the driver's "no such column" is swallowed, and the list comes back
-empty and indistinguishable from *"there is no data"*. Each position of a filter
-is judged on its own, so the field above is still checked even though `stage`
-comes from React state.
+An unknown column in a predicate is not a skipped column — the SQL drivers
+refuse it with `INVALID_FILTER` / 400, naming the column, instead of running
+the predicate. The remedy is to run schema sync so the declared field has its
+column, or to name a column the table has. Catching it here, before the page
+ships, means an author sees the mistake in the editor instead of a 400 in
+production. Each position of a filter is judged on its own, so the field above
+is still checked even though `stage` comes from React state.
 
 Skipped, to keep false positives at zero: the same set as §8 — non-static
 values, `{...spread}` usages, relationship paths, system fields, and objects