[Feat] Add Cloudflare built-in integration

[roomote-roomote]

​Opened on behalf of @daniel-lxs. Follow up by mentioning @roomote-roomote, in the web UI, or in Telegram.

What changed

• Added Cloudflare to the existing MCP_INTEGRATIONS registry with its official hosted MCP endpoint, deployment-scoped OAuth/DCR connection, OAuth resource, and explicit-mutation guidance.
• Reused the existing Settings integration list and generic OAuth connection flow. Integrations.tsx continues to render directly from MCP_INTEGRATIONS; this adds no new list, section, or special UI.
• Wired the shared URL-detection registry into active Slack agent context so pasted Cloudflare dashboard links trigger built-in integration setup guidance.
• Added the Simple Icons Cloudflare mark, self-setup and Slack recommendation metadata, task setup guidance, focused registry/runtime tests, and the public docs page/overview/navigation entry.

Why this change was made

Cloudflare provides an official remote MCP server with public OAuth metadata for dynamic client registration and PKCE. Adding it to the curated registry gives deployment operators the same built-in setup path used by existing hosted MCP integrations.

Impact

Operators can connect Cloudflare once from Settings > Integrations, and pasted dashboard links now give Slack tasks an explicit setup recommendation when the built-in integration is unavailable. URL parsing uses bounded punctuation handling rather than the regex flagged by CodeQL, with direct repeated-punctuation coverage. Focused URL-detection, Slack-context, and event-normalization tests passed alongside full check-types, lint:fast, and git diff --check. Live OAuth consent, tools/list, and credential-backed provider calls were not performed.

Related PRs

• Stripe #2995
• CircleCI #2993
• Buildkite #2994

[roomote-community]

No new code issues found. See task

• Cloudflare dashboard URL detection is not wired to a runtime consumer.

_{Reviewed 7bbdfc2}