Suppress deprecated and notice-level warnings from UI output

[LogicVortex123]

PR: Clean UI by Suppressing Deprecated & Notice Warnings

This PR enhances the user interface by hiding PHP E_DEPRECATED and E_NOTICE warnings that clutter the UI, while keeping fatal and critical errors visible for debugging. Users now see a cleaner, more professional interface without affecting application functionality.

Changes Made:

• Updated global error reporting to exclude deprecated and notice-level warnings
• Disabled on-screen display of non-critical warnings using ini_set('display_errors', 'Off')

Motivation:
Addresses Issue #1660 by preventing non-actionable warnings from distracting users, improving usability and presentation without altering backend logic.

Scope & Safety:

• UI-only improvement
• No functional, database, or schema changes
• Low-risk; critical errors remain unaffected

Testing:

• Verified locally that deprecated and notice-level PHP warnings are not rendered during application boot and installer flow on localhost.

[LogicVortex123]

Hi, I’d appreciate a review when possible. Happy to make any changes!