[WEB-273] Update WebSDK integration snippet to new format

[Aman-engg-sdk]

WEB-273 Update WebSDK integration snippet to new format

Summary

Updates the MoEngage WebSDK loader snippet across all 13 integration sample files to the latest format. The new snippet adds versioned CDN URL support, a stricter data-center validation regex, an expanded API stubs list, and fixes the double-init guard to handle both US/UK spellings of "initialized".

Changes

• Replace old IIFE with new snippet (regex DC validation, versioned CDN URL)
• Add var sdkVersion = "2" to all integration files
• Expand stub methods list with 18 new API methods (setLogLevel, identifyUser, etc.)
• Fix double-init guard: check both initialized and initialised
• Change app_id: to appId: in all moe() init calls
• Migrate eu-cluster.html from legacy hardcoded webpush URL to DC-based format

Files Changed

index.html, self-handled-push.html, custom-serviceworker.html, web-personalization.html, debug.html, eu-cluster.html, angular-sample/src/index.html, react-sample/public/index.html, lg-web-os/index.html, samsung-tizen-os/samsungTizenOs/index.html, nuxt-spa/plugins/moe.js, nextjs/pages/_document.js, chrome-extension/popup.js

Tech Stack

Plain HTML/JS integration samples covering: Vanilla JS, Angular, React, Nuxt.js (SPA), Next.js, Chrome Extension, LG WebOS, Samsung Tizen OS — all integrating the MoEngage WebSDK via CDN loader snippet.

CSS Architecture

N/A — this PR contains no CSS changes.

Bundle Optimization

N/A — snippet changes are minimal (~41 insertions / 27 deletions). The new versioned CDN URL (/versions/2/) pins the SDK to a major version, avoiding unintended breaking updates.

Code Quality

• All 13 files pass a 6-point validation matrix (new IIFE, sdkVersion, appId, versioned CDN, no old patterns)
• No TypeScript or lint tooling applies to these static HTML/JS samples

Jira Ticket

WEB-273

Release Ticket

N/A

Test Cases

N/A

Testing Done

• All 13 files validated: new IIFE, sdkVersion, appId, CDN URL, no old patterns
• Manual browser test with a valid dc_X value