Remove backward compatibility support for `title.md` for the next major release

[ashmitahaldar]

Description

In PR #2516, the dashboard’s introductory section was renamed from title.md to intro.md to resolve naming conflicts with the browser tab title field. While that PR introduced the new naming convention, it maintained backward compatibility to allow users time to migrate.

As planned, we should now remove this deprecated support in the next major feature release to simplify the codebase and prevent long-term maintenance overhead.

Current State

Currently, the system performs a fallback check:

• It looks for intro.md.
• If not found, it falls back to title.md and triggers a deprecation warning.

Related Links

• Original issue: Renaming title.md  #2318
• Previous PR: [#2318] Rename title.md #2516