fix(a11y): hide decorative SVGs from assistive tech

[adityakulraj]

Summary

• add aria-hidden="true" to decorative inline SVGs in layouts/index.html
• cover decorative icons in the header, controls, dialogs, quick links, report links, and generated service icon templates
• keep the existing button labels and nearby text as the accessible names

Testing

• git diff --check
• verified there are no remaining <svg tags in layouts/index.html without aria-hidden

Closes #78

[adityakulraj]

@comnam90 would appreciate your review on this one too when you have time. Thanks!

[Copilot]

Pull request overview

This PR improves the accessibility of the Hugo-based single-page map UI (layouts/index.html) by marking decorative inline SVG icons as hidden from assistive technologies, reducing screen reader noise while preserving existing accessible names via surrounding text and aria-labels.

Changes:

• Adds aria-hidden="true" to decorative inline SVGs across header controls, dialogs/panels, quick links, and report links.
• Adds aria-hidden="true" to SVGs returned by getServiceIcon() (including the fallback icon template).