Feat/multi model provider support (#692)

* test: add tests for provider model env updates and multi-model profiles

Add comprehensive tests covering:
- OPENAI_MODEL/ANTHROPIC_MODEL env updates on provider activation
- Cross-provider type switches (openai ↔ anthropic) clearing stale env
- Multi-model profile activation using only the first model for env vars
- Model options cache population from comma-separated model lists
- getProfileModelOptions generating correct ModelOption arrays

* feat: multi-model provider support and model auto-switch

Support comma-separated model names in provider profiles (e.g.
"glm-4.7, glm-4.7-flash"). The first model is used as default on
activation; all models appear in the /model picker for easy switching.

When switching active providers, the session model now automatically
updates to the new provider's first model. The multi-model list is
preserved across switches and /model selections.

Changes:
- Add parseModelList, getPrimaryModel, hasMultipleModels utilities
  with full test coverage (19 tests)
- Use getPrimaryModel when applying profiles to process.env so only
  the primary model is set in OPENAI_MODEL/ANTHROPIC_MODEL
- Update ProviderManager UI to hint at multi-model syntax and show
  model count in provider list summaries
- Populate model options cache from multi-model profiles on activation
  so all models appear in /model picker regardless of base URL type
- Guard persistActiveProviderProfileModel against overwriting
  comma-separated lists: models already in the profile are session
  selections, not profile edits
- Set AppState.mainLoopModel to the actual model string on provider
  switch so Anthropic profiles use the configured model instead of
  falling back to the built-in default

* fix: only show profile models when provider profile env is applied

Guard the profile model picker options behind a
PROFILE_ENV_APPLIED check. getActiveProviderProfile() has a
?? profiles[0] fallback that returns the first profile even when
no profile is explicitly active, causing users with inactive
profiles to lose all standard model options (Opus, Haiku, etc.)
from the /model picker.

* fix: show all model names for profiles with 3 or fewer models

Instead of a summary format for multi-model profiles, display all
model names when there are 3 or fewer. Only use the "+ N more"
format for profiles with 4+ models.

* fix: preserve standard model options in picker alongside profile models

The previous implementation used an early return that replaced all
standard picker options (Opus, Haiku, Sonnet for Anthropic; Codex/GPT
models for OpenAI) with only the profile's custom models.

Changes:
- Collect profile models into a shared array instead of early returning
- Append profile models to firstParty path (Opus + Haiku + Sonnet + custom)
- Append profile models to PAYG 3P path (Codex + Sonnet + Opus + Haiku + custom)
- Guard collection behind PROFILE_ENV_APPLIED to avoid ?? profiles[0] fallback

Fixes review feedback: standard models are no longer hidden when a
provider profile with custom models is active. Users see both the
standard options and their profile's models.

---------

Co-authored-by: Ali Alakbarli <ali.alakbarli@users.noreply.github.com>

src/components/ProviderManager.tsx

@@ -9,6 +9,7 @@ import {
   readCodexCredentialsAsync,
 } from '../utils/codexCredentials.js'
 import { isBareMode, isEnvTruthy } from '../utils/envUtils.js'
+import { getPrimaryModel, hasMultipleModels, parseModelList } from '../utils/providerModels.js'
 import {
   applySavedProfileToCurrentSession,
   buildCodexOAuthProfileEnv,
@@ -50,6 +51,7 @@ import {
 import { Pane } from './design-system/Pane.js'
 import TextInput from './TextInput.js'
 import { useCodexOAuthFlow } from './useCodexOAuthFlow.js'
+import { useSetAppState } from '../state/AppState.js'
 
 export type ProviderManagerResult = {
   action: 'saved' | 'cancelled'
@@ -108,8 +110,8 @@ const FORM_STEPS: Array<{
   {
     key: 'model',
     label: 'Default model',
-    placeholder: 'e.g. llama3.1:8b',
-    helpText: 'Model name to use when this provider is active.',
+    placeholder: 'e.g. llama3.1:8b or glm-4.7, glm-4.7-flash',
+    helpText: 'Model name(s) to use. Separate multiple with commas; first is default.',
   },
   {
     key: 'apiKey',
@@ -153,7 +155,12 @@ function profileSummary(profile: ProviderProfile, isActive: boolean): string {
   const keyInfo = profile.apiKey ? 'key set' : 'no key'
   const providerKind =
     profile.provider === 'anthropic' ? 'anthropic' : 'openai-compatible'
-  return `${providerKind} · ${profile.baseUrl} · ${profile.model} · ${keyInfo}${activeSuffix}`
+  const models = parseModelList(profile.model)
+  const modelDisplay =
+    models.length <= 3
+      ? models.join(', ')
+      : `${models[0]}, ${models[1]} + ${models.length - 2} more`
+  return `${providerKind} · ${profile.baseUrl} · ${modelDisplay} · ${keyInfo}${activeSuffix}`
 }
 
 function getGithubCredentialSourceFromEnv(
@@ -320,6 +327,7 @@ function CodexOAuthSetup({
 }
 
 export function ProviderManager({ mode, onDone }: Props): React.ReactNode {
+  const setAppState = useSetAppState()
   const initialGithubCredentialSource = getGithubCredentialSourceFromEnv()
   const initialIsGithubActive = isEnvTruthy(process.env.CLAUDE_CODE_USE_GITHUB)
   const initialHasGithubCredential = initialGithubCredentialSource !== 'none'
@@ -573,6 +581,10 @@ export function ProviderManager({ mode, onDone }: Props): React.ReactNode {
         }
 
         refreshProfiles()
+        setAppState(prev => ({
+          ...prev,
+          mainLoopModel: GITHUB_PROVIDER_DEFAULT_MODEL,
+        }))
         setStatusMessage(`Active provider: ${GITHUB_PROVIDER_LABEL}`)
         setScreen('menu')
         return
@@ -585,6 +597,16 @@ export function ProviderManager({ mode, onDone }: Props): React.ReactNode {
         return
       }
 
+      // Update the session model to the new provider's first model.
+      // persistActiveProviderProfileModel (called by onChangeAppState) will
+      // not overwrite the multi-model list because it checks if the model
+      // is already in the profile's comma-separated model list.
+      const newModel = getPrimaryModel(active.model)
+      setAppState(prev => ({
+        ...prev,
+        mainLoopModel: newModel,
+      }))
+
       providerLabel = active.name
       const settingsOverrideError =
         clearStartupProviderOverrideFromUserSettings()