Fix undefined echo.Map in homepage Hello World example

[wakqasahmed]

Summary

The homepage Hello World example (site/src/components/HomeHero.astro) used echo.Map{"message": "Hello, World!"}, but echo.Map does not exist as a type in Echo v5. Copying the homepage example as-is fails to compile.

This replaces it with a plain map[string]string{"message": "Hello, World!"}, matching the pattern already used in the v5 Quickstart docs.

Why this PR targets echox instead of echo

The issue was filed on labstack/echo (labstack/echo#3065) because that's the natural place to report a docs/website bug, but the homepage/website source actually lives in this repo (labstack/echox). This PR fixes the bug where the code actually lives.

Fixes labstack/echo#3065

Test plan

• npm ci && npx astro build in site/ completes successfully with no errors
• Confirmed echo.Map no longer appears anywhere in the built output
• Confirmed the Echo v5 Context.JSON(code int, i any) signature accepts map[string]string, so the example now compiles as advertised