docs: Claude Code CLI plugin docs

[daveomri]

Adds a guide for the new Apify plugin for Claude Code, walking end users through the CLI install flow (no UI app coverage yet - the app is still in development).

The page covers:

• What the plugin bundles: the Apify MCP server, the apify routing agent, and five skills (ultimate scraper, Actor development, actorization, output-schema generation, SDK integration).
• Install via the GitHub repo as a marketplace: /plugins → Marketplaces → Add Marketplace → https://github.com/apify/apify-claude-code-plugin → Discover → install with scope → /reload-plugins.
• Authentication via /mcp: Enable plugin:apify:apify, then re-open it and run Authenticate to complete the Apify OAuth flow (with a caution callout for the dynamic-registration warning).
• Try-it prompt, troubleshooting (disabled plugin, /plugins unavailable, OAuth fallback to APIFY_TOKEN), and limitations.

Assets added:

• 14 step-numbered screenshots under sources/platform/integrations/ai/images/claude_code_cli/.
• Claude symbol icon at static/img/platform/integrations/claude-code.svg (from Wikimedia Commons).
• New card in the AI/LLM grid on the integrations landing page.