Extracts the Meta JS SDK logic for the WhatsApp embedded-signup and Facebook Page connect flows out of their settings components into two reusable composables. No behavior change — the settings inbox-creation flows work exactly as before; this just makes the SDK orchestration reusable (an upcoming onboarding PR consumes them) and adds unit coverage. ## What changed - `useWhatsappEmbeddedSignup` — owns the embedded-signup popup (SDK load, FB.login, and the auth-code / postMessage race). `WhatsappEmbeddedSignup.vue` now consumes it. - `useFacebookPageConnect` — owns FB.login (page scopes) + page fetch, with SDK preload split from login so the popup opens within the click's activation window. `Facebook.vue` now consumes it. - Adds unit specs for both composables. ## Related PRs - https://github.com/chatwoot/chatwoot/pull/14569 - https://github.com/chatwoot/chatwoot/pull/14568 - https://github.com/chatwoot/chatwoot/pull/14567 - https://github.com/chatwoot/chatwoot/pull/14649 - https://github.com/chatwoot/chatwoot/pull/14565 (Primary onboarding PR)