[AI-8410] Feature: Host apps can load Angie sidebar with v2 config

[matipojo]

Problem

Host applications integrating Angie need a structured way to boot the sidebar with host-specific context (appId, website, aiContext), container options, and iframe settings. The current SDK surface does not expose a dedicated v2 load API for this.

Solution

Add loadSidebarV2 to AngieMcpSdk with a configurable options model, config resolution, container/shell setup, and embedded host handshake.

Jira: https://elementor.atlassian.net/browse/AI-8410

[matipojo]

Superseded by stacked review PRs for the same AI-8410 work:

1. Core sidebar API → [AI-8410] Feature: Host apps can load Angie sidebar with v2 config — core sidebar API #43 (AI-8410-v2-core → master)
2. Layouts and chat toggle → [AI-8410] Feature: Host apps can load Angie sidebar with v2 config — layouts and chat toggle #44 (AI-8410-v2-layouts → AI-8410-v2-core)
3. Host API bridge → [AI-8410] Feature: Host apps can load Angie sidebar with v2 config — host API bridge #45 (AI-8410-v2-host-bridge → AI-8410-v2-layouts)

Original branch AI-8410-load-sidebar-v2 and backup ref refs/backup/AI-8410-load-sidebar-v2 are unchanged for reference. Closing this draft in favor of the stack.