fix(channels): reveal advanced validation errors

- add channel form error detection for JSON validation errors inside advanced settings.
- expand advanced settings on invalid channel drawer submit and prompt users to fix highlighted fields.
- add regression tests for advanced error detection, non-advanced exclusions, and schema error classification.

web/default/src/features/channels/lib/channel-form-errors.ts

@@ -0,0 +1,67 @@
+/*
+Copyright (C) 2023-2026 QuantumNous
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+For commercial licensing, please contact support@quantumnous.com
+*/
+import type { FieldPath } from 'react-hook-form'
+import type { ChannelFormValues } from './channel-form'
+
+type ChannelFormErrorMap = Partial<
+  Record<FieldPath<ChannelFormValues>, unknown>
+>
+
+const ADVANCED_SETTINGS_FIELDS = new Set<FieldPath<ChannelFormValues>>([
+  'priority',
+  'weight',
+  'test_model',
+  'auto_ban',
+  'tag',
+  'remark',
+  'model_mapping',
+  'param_override',
+  'header_override',
+  'status_code_mapping',
+  'force_format',
+  'thinking_to_content',
+  'pass_through_body_enabled',
+  'proxy',
+  'system_prompt',
+  'system_prompt_override',
+  'allow_service_tier',
+  'disable_store',
+  'allow_safety_identifier',
+  'allow_include_obfuscation',
+  'allow_inference_geo',
+  'allow_speed',
+  'claude_beta_query',
+  'upstream_model_update_check_enabled',
+  'upstream_model_update_auto_sync_enabled',
+  'upstream_model_update_ignored_models',
+])
+
+export function isAdvancedSettingsField(
+  fieldName: string
+): fieldName is FieldPath<ChannelFormValues> {
+  return ADVANCED_SETTINGS_FIELDS.has(fieldName as FieldPath<ChannelFormValues>)
+}
+
+export function hasAdvancedSettingsErrors(
+  errors: ChannelFormErrorMap
+): boolean {
+  return Object.keys(errors).some((fieldName) =>
+    isAdvancedSettingsField(fieldName)
+  )
+}