docs: mark GIX Components as in maintenance mode (README)

[AntonioVentilii]

Motivation

GIX Components is moving to maintenance mode: it receives critical fixes only, no new features, and is not recommended for new projects. We want this stated up front in the README. Since the README ships to npm (files in package.json), the warning will also render on the npm package page on the next published release.

Changes

• Add a > [!WARNING] maintenance-mode callout at the top of README.md.

Screenshots

N/A — README text only. Renders as a GitHub/npm warning callout.

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to 49133be.

Security Overview

• 🔎 Scanned files: 1 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/98bf2300-834e-44ab-93d0-06f69eae67e3?scanId=23b3fe80-e9ff-4f45-a9c3-44d8bb9d438f&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Other relevant categories	► README.md     Add maintenance mode warning to README