fix: decode html entities in widget titles

[Pranjal1423]

Closes #393

Description

This PR fixes a visual bug where HTML entities in post titles (e.g. & or ’) were rendered raw inside built-in desktop widgets (such as Recent Comments and the Starter Widget).

Root Causes & Fixes

Missing Entity Decoding in Widgets:
Issue: The REST API returns titles with HTML-encoded entities in the title.rendered payload. The widgets were setting this raw payload directly to textContent, causing the browser to render the raw entity codes (like Q&A: User’s Guide).

Fix: Created a shared utility decodeHTML inside utils.ts that safely decodes HTML entities by parsing them through a temporary DOM textarea element. Both recent-comments-widget/index.ts and starter-widget/index.ts now import and apply decodeHTML to titles before updating the UI.

Code Duplication:

Issue: The Posts window already had a local decodeTitle function doing identical DOM-based decoding, creating redundant code.
Fix: Refactored posts-window/index.ts to import and reuse the shared decodeHTML utility from utils.ts.

Verification

Build: npm run build completed successfully.
Typecheck: npm run typecheck passed with no errors.
Unit Tests: npm run test:js and npm run test:php both completed successfully with all tests passing (1601/1601 JS tests and 1017/1017 PHP tests).

Before fix

• Raw HTML entities rendered under commenter name: ↳ Q&A: User’s Guide

After fix

• Clean, decoded titles: ↳ Q&A: User’s Guide

[AllTerrainDeveloper]

Thank you very much!

[AllTerrainDeveloper]

Nice move!

[Pranjal1423]

Thankyou!!