fix custom provider credentials, edit path, and failure UX

Require an API key or {env:VAR} on client and server, add edit/prefill for
existing custom providers, save auth before config, and surface incomplete
auth plus disconnect after partial failures. Add VS Code parity tests and
drop the unused allProvidersConnected locale key.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/ui/src/components/sections/providers/custom-provider-form.test.ts

@@ -2,8 +2,10 @@ import { describe, expect, test } from 'bun:test';
 import {
   buildAuthSetRequest,
   buildProviderUpsertRequest,
-  mergeProviderConfig,
+  isCustomOpenAICompatibleProvider,
+  providerToCustomFormState,
   validateCustomProvider,
+  type CustomProviderConfig,
   type CustomProviderFormState,
 } from './custom-provider-form';
 
@@ -19,6 +21,28 @@ const baseForm = (overrides: Partial<CustomProviderFormState> = {}): CustomProvi
   ...overrides,
 });
 
+/** Mirrors server upsert semantics for request-construction tests. */
+function mergeProviderConfig(
+  existing: Record<string, unknown>,
+  providerID: string,
+  config: CustomProviderConfig,
+): Record<string, unknown> {
+  const providerSection = (
+    typeof existing.provider === 'object' && existing.provider !== null && !Array.isArray(existing.provider)
+      ? { ...(existing.provider as Record<string, unknown>) }
+      : {}
+  );
+  providerSection[providerID] = config;
+  const next: Record<string, unknown> = {
+    ...existing,
+    provider: providerSection,
+  };
+  if (Array.isArray(existing.disabled_providers)) {
+    next.disabled_providers = existing.disabled_providers.filter((entry) => entry !== providerID);
+  }
+  return next;
+}
+
 describe('validateCustomProvider', () => {
   test('builds trimmed config and auth payloads', () => {
     const result = validateCustomProvider({
@@ -70,6 +94,31 @@ describe('validateCustomProvider', () => {
     expect(result.result?.config.env).toEqual(['CUSTOM_PROVIDER_KEY']);
   });
 
+  test('rejects missing credentials', () => {
+    const result = validateCustomProvider({
+      form: baseForm({ apiKey: '   ' }),
+      t,
+      existingProviderIDs: new Set(),
+    });
+
+    expect(result.result).toEqual(undefined);
+    expect(result.err.apiKey).toBe('settings.providers.page.custom.error.apiKey.required');
+  });
+
+  test('allows empty api key when editing with existing auth', () => {
+    const result = validateCustomProvider({
+      form: baseForm({ apiKey: '' }),
+      t,
+      existingProviderIDs: new Set(['custom-provider']),
+      editingProviderID: 'custom-provider',
+      allowExistingAuth: true,
+    });
+
+    expect(result.result?.providerID).toBe('custom-provider');
+    expect(result.err.apiKey).toEqual(undefined);
+    expect(result.result?.apiKey).toEqual(undefined);
+  });
+
   test('rejects invalid provider id, base URL, and duplicate rows', () => {
     const result = validateCustomProvider({
       form: baseForm({
@@ -113,7 +162,7 @@ describe('validateCustomProvider', () => {
     expect(result.err.providerID).toEqual(undefined);
   });
 
-  test('rejects an already-connected provider id', () => {
+  test('rejects an already-connected provider id on create', () => {
     const result = validateCustomProvider({
       form: baseForm(),
       t,
@@ -123,6 +172,18 @@ describe('validateCustomProvider', () => {
     expect(result.result).toEqual(undefined);
     expect(result.err.providerID).toBe('settings.providers.page.custom.error.providerID.exists');
   });
+
+  test('allows updating the same provider id while editing', () => {
+    const result = validateCustomProvider({
+      form: baseForm({ apiKey: 'sk-updated' }),
+      t,
+      existingProviderIDs: new Set(['custom-provider']),
+      editingProviderID: 'custom-provider',
+    });
+
+    expect(result.result?.providerID).toBe('custom-provider');
+    expect(result.err.providerID).toEqual(undefined);
+  });
 });
 
 describe('request construction', () => {
@@ -200,3 +261,31 @@ describe('mergeProviderConfig persistence shape', () => {
     });
   });
 });
+
+describe('provider edit helpers', () => {
+  test('detects openai-compatible custom providers and prefills form state', () => {
+    expect(isCustomOpenAICompatibleProvider({
+      id: 'campus-llm',
+      options: { baseURL: 'https://llm.example.edu/v1' },
+      models: [],
+    })).toBe(true);
+
+    const state = providerToCustomFormState({
+      id: 'campus-llm',
+      name: 'Campus LLM',
+      env: ['CAMPUS_KEY'],
+      options: {
+        baseURL: 'https://llm.example.edu/v1',
+        headers: { 'X-Campus': '1' },
+      },
+      models: [{ id: 'fast', name: 'Fast' }],
+    });
+
+    expect(state.providerID).toBe('campus-llm');
+    expect(state.name).toBe('Campus LLM');
+    expect(state.baseURL).toBe('https://llm.example.edu/v1');
+    expect(state.apiKey).toBe('{env:CAMPUS_KEY}');
+    expect(state.models[0]).toEqual({ row: state.models[0].row, id: 'fast', name: 'Fast' });
+    expect(state.headers[0]).toEqual({ row: state.headers[0].row, key: 'X-Campus', value: '1' });
+  });
+});