feat: GitHub provider lifecycle and onboarding hardening (#351)

* feat: improve GitHub provider onboarding and lifecycle

* fix: address copilot review in provider manager

* fix: address follow-up copilot review comments

* test: resolve rebase conflict in provider profiles suite

* fix: clear stale github hydrated marker

* fix: harden github onboarding auth precedence

* fix: remove merge markers from provider tests

* fix: resolve latest copilot onboarding comments

---------

Co-authored-by: KRATOS <84986124+gnanam1990@users.noreply.github.com>

src/utils/model/modelOptions.ts

@@ -352,6 +352,18 @@ function getCodexModelOptions(): ModelOption[] {
 // @[MODEL LAUNCH]: Update the model picker lists below to include/reorder options for the new model.
 // Each user tier (ant, Max/Team Premium, Pro/Team Standard/Enterprise, PAYG 1P, PAYG 3P) has its own list.
 function getModelOptionsBase(fastMode = false): ModelOption[] {
+  if (getAPIProvider() === 'github') {
+    const githubModel = process.env.OPENAI_MODEL?.trim() || 'github:copilot'
+    return [
+      getDefaultOptionForUser(fastMode),
+      {
+        value: githubModel,
+        label: githubModel,
+        description: 'GitHub Models default',
+      },
+    ]
+  }
+
   // When using Ollama, show models from the Ollama server instead of Claude models
   if (getAPIProvider() === 'openai' && isOllamaProvider()) {
     const defaultOption = getDefaultOptionForUser(fastMode)
@@ -579,6 +591,10 @@ function getKnownModelOption(model: string): ModelOption | null {
 }
 
 export function getModelOptions(fastMode = false): ModelOption[] {
+  if (getAPIProvider() === 'github') {
+    return filterModelOptionsByAllowlist(getModelOptionsBase(fastMode))
+  }
+
   const options = getModelOptionsBase(fastMode)
 
   // Add the custom model from the ANTHROPIC_CUSTOM_MODEL_OPTION env var