docs(readme): add a centered header with logo, links and screenshot

[devGregA]

What

Replaces the badge table at the top of the README with a centered header:

• Logo that follows the viewer's GitHub theme, using the existing docs/static/svgs/logo-lightmode.svg and logo-darkmode.svg in a <picture> element.
• One-line description and a link row: Pro demo, Community demo, Docs, Slack, Community, Website. The two demo links carry utm_source=github&utm_medium=readme, so visits from the README can be counted in the demo servers' access logs.
• Badges unchanged, now in one centered row, with the Open Source Security Index badge below them. This also drops the table's malformed styl= attribute.
• Screenshot of the Pro home page in light and dark variants (readme-docs/images/pro-home-{light,dark}.png, 2000×1193, about 0.7 MB each), shown to match the viewer's theme. It links to the Pro demo and is captioned as DefectDojo Pro, with a pointer to the Community demo and the existing Demo section for sign-in details.

Everything from the Demo section down is unchanged.

How the screenshots were made

Captured with Playwright from a Pro instance with sample data, at a 1920×1200 viewport and 2× scale, once with prefers-color-scheme: light and once with dark. The signed-in user row at the bottom of the sidebar is cropped out, and the images are resized to 2000 px wide. No text or pixels were edited. The visible data shows scan-tool names only, with no product or organization names.

Checked

Rendered from the pushed branch on GitHub:

• Light mode: dark-teal logo and the light screenshot.
• Dark mode: orange logo and the dark screenshot.
• Both srcset paths are rewritten by GitHub to /raw/<branch>/... URLs, so they resolve.
• At 1280 px, the screenshot fills the README column (845 px).
• At 375 px, it scales to 308 px with no horizontal overflow.
• The #demo anchor in the caption resolves.
• Both demo URLs with the query string redirect to their login pages and return 200.

🤖 Generated with Claude Code