feat: improve accessibility - ARIA labels, keyboard nav, screen reade…

[shresthbhargava]

Closes #123

What's Changed

script.js

• Added role="region" and aria-label to all result cards so screen readers announce scan outcomes
• Focus is moved to the result div after every scan — screen readers immediately read the result
• Scan button now uses aria-busy="true" while scanning and updates its aria-label to "Scanning URL, please wait..."
• Theme toggle now uses aria-pressed and descriptive labels ("Switch to light/dark mode")
• All decorative SVG icons marked aria-hidden="true" so screen readers skip them
• Emoji status indicators wrapped with aria-hidden="true" + adjacent .sr-only text for screen reader meaning
• Breakdown lists use role="list" + role="listitem" for proper screen reader navigation
• Risk meter uses role="progressbar" with aria-valuenow, aria-valuemin, aria-valuemax
• Team grid gets role="list" with each card as role="listitem"
• fillExample() updates aria-label on input to reflect filled value

index.html

• Added type="button" to all buttons to prevent accidental form submission
• Loader div gets role="alert" and aria-live="assertive"
• Decorative SVGs marked aria-hidden="true"
• Result div has aria-live="polite", aria-atomic="true", role="status"

style.css

• Added :focus-visible outline using brand color #00ffb4 for keyboard users
• Added :focus:not(:focus-visible) to remove outline for mouse users only
• Added .sr-only utility class for screen-reader-only text

Testing

• Tabbed through all interactive elements — logical focus order confirmed
• Scan button, example chips, theme toggle, team toggle all keyboard accessible
• Screen reader announces scan result immediately after completion

[Mrinalray]

@shresthbhargava add some screenshot & resolve the script.js conflict