docs: inline Azure DevOps card icon so it follows dark mode

[devin-ai-integration]

Summary

Follow-up to #68. Mintlify renders a path-based icon="/images/azure-devops.svg" as an <img>, so fill="currentColor" in the file has no effect and the icon stayed black in dark mode.

Cards now pass the SVG inline as JSX (icon={<svg fill="currentColor">…</svg>}), which Mintlify wraps in the same text-gray-800 dark:text-gray-100 container as the Font Awesome icons, so it flips with the theme. Applied to all four Azure DevOps cards (code-review/setup, platform/repositories, platform/integrations, code-review/integrations/github-gitlab); images/azure-devops.svg is removed as nothing references it anymore.

Dark mode (local preview):

Link to Devin session: https://app.devin.ai/sessions/211b97f54c6e4dcf980fe1f5b65b504e
Open in Devin Desktop: https://app.devin.ai/desktop/session/211b97f54c6e4dcf980fe1f5b65b504e?variant=devin

[devin-ai-integration]

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