docs: add max_scale to the hand-written field-level error catalog (#7501)

The group table in content/docs/api/error-catalog.mdx enumerates the closed
FieldErrorCode catalog exhaustively (27 members pre-change, one per group
row); max_scale joins the bounded-ranges row after max_value, matching the
enum's own ordering. The three example lines above the table are illustrative
(3 of 27 codes, mirroring the errors.zod.ts doc examples) and stay as-is.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RDTnVvsgA6cUZ4xFVtPZRy

Author: claude

content/docs/api/error-catalog.mdx

@@ -528,7 +528,7 @@ snake_case, so the code and the schema property are the same word.
 |:---|:---|
 | Presence and shape | `required`, `invalid_type`, `invalid_shape`, `unknown_field` |
 | Per-type parse | `invalid_boolean`, `invalid_number`, `invalid_date`, `invalid_time`, `invalid_email`, `invalid_url`, `invalid_phone`, `invalid_json`, `invalid_format` |
-| Bounded ranges | `min_length`, `max_length`, `min_value`, `max_value`, `min_items`, `max_items` |
+| Bounded ranges | `min_length`, `max_length`, `min_value`, `max_value`, `max_scale`, `min_items`, `max_items` |
 | Closed sets and references | `invalid_option`, `invalid_value`, `reference_not_found`, `reference_ambiguous` |
 | Declarative rules | `rule_violation`, `json_schema_violation`, `invalid_initial_state`, `invalid_transition` |