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

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

src/commands/onboard-github/index.ts

@@ -2,6 +2,7 @@ import type { Command } from '../../commands.js'
 
 const onboardGithub: Command = {
   name: 'onboard-github',
+  aliases: ['onboarding-github', 'onboardgithub', 'onboardinggithub'],
   description:
     'Interactive setup for GitHub Models: device login or PAT, saved to secure storage',
   type: 'local-jsx',