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/components/drawers/channel-mutate-drawer.tsx

@@ -24,7 +24,7 @@ import {
   useCallback,
   useRef,
 } from 'react'
-import { useForm } from 'react-hook-form'
+import { type SubmitErrorHandler, useForm } from 'react-hook-form'
 import { zodResolver } from '@hookform/resolvers/zod'
 import { useQuery, useQueryClient } from '@tanstack/react-query'
 import {
@@ -140,6 +140,7 @@ import {
   hasModelConfigChanged,
   findMissingModelsInMapping,
   validateModelMappingJson,
+  hasAdvancedSettingsErrors,
 } from '../../lib'
 import {
   collectInvalidStatusCodeEntries,
@@ -1008,6 +1009,26 @@ export function ChannelMutateDrawer({
     ]
   )
 
+  const handleAdvancedSettingsOpenChange = useCallback((nextOpen: boolean) => {
+    setAdvancedSettingsOpen(nextOpen)
+    if (typeof window !== 'undefined') {
+      window.localStorage.setItem(
+        ADVANCED_SETTINGS_EXPANDED_KEY,
+        String(nextOpen)
+      )
+    }
+  }, [])
+
+  const onInvalid: SubmitErrorHandler<ChannelFormValues> = useCallback(
+    (errors) => {
+      if (hasAdvancedSettingsErrors(errors)) {
+        handleAdvancedSettingsOpenChange(true)
+      }
+      toast.error(t('Please fix the highlighted fields before saving'))
+    },
+    [handleAdvancedSettingsOpenChange, t]
+  )
+
   // Handle drawer close
   const handleOpenChange = useCallback(
     (v: boolean) => {
@@ -1020,16 +1041,6 @@ export function ChannelMutateDrawer({
     [onOpenChange, form]
   )
 
-  const handleAdvancedSettingsOpenChange = useCallback((nextOpen: boolean) => {
-    setAdvancedSettingsOpen(nextOpen)
-    if (typeof window !== 'undefined') {
-      window.localStorage.setItem(
-        ADVANCED_SETTINGS_EXPANDED_KEY,
-        String(nextOpen)
-      )
-    }
-  }, [])
-
   return (
     <>
       <Sheet open={open} onOpenChange={handleOpenChange}>
@@ -1060,7 +1071,7 @@ export function ChannelMutateDrawer({
           <Form {...form}>
             <form
               id='channel-form'
-              onSubmit={form.handleSubmit(onSubmit)}
+              onSubmit={form.handleSubmit(onSubmit, onInvalid)}
               className={sideDrawerFormClassName('gap-5')}
             >
               {isChannelDetailLoading ? (