feat(ui-rewrite): add useMCPServerForm hook for creating and editing MCP servers

[marekdano]

🔗 Related Issue

Related #4175

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📝 Summary

Add a hook for creating and editing MCP servers. The hook contains calls to API endpoints to create or edit MCP Servers.

create_mcp_server.mov

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🏷️ Type of Change

• Bug fix
• Feature / Enhancement
• Documentation
• Refactor
• Chore (deps, CI, tooling)
• Other (describe below)

[a-effort]

🤖 Sonnet 4.6 review feedback:

Good structure here: extracting form logic into a dedicated hook with Zod validation and sanitization is the right call. A few things worth flagging...

1. Zod v4 is a breaking change: package.json bumps to zod@^4.4.1, but shadcn has a nested zod@3.25.76 as a peer dependency (visible in package-lock.json). Zod v4 has breaking API changes. If shadcn uses zod internally for form validation (e.g., via react-hook-form + zod resolvers), this version split will cause runtime issues. Worth verifying compatibility with the full shadcn setup.

2. sanitizeCertificate calls .trim() on the result (sanitize.ts:130)... PEM certs sometimes require a trailing \n after -----END CERTIFICATE----- and some TLS parsers reject trimmed certs. Easy fix now, easy to forget later.

3. There's a stray // Made with Bob comment at the end of useMCPServerForm.test.ts that should be removed.

Worth noting before this goes to production:

• handleSubmit is typed as returning void in the interface but the implementation is async. It should be Promise.
• isValid only checks that name/URL are non-empty, not that the URL is valid (acceptable for a prototype but will need tightening for real validation UX).
• passthroughHeaders is stored as a comma-separated string but the Zod schema expects z.array(z.string()), so
  validateField("passthroughHeaders", ...) won't behave as expected. Worth a // TODO comment so it's not a surprise when edit mode gets wired up. Same goes for the missing pre-population logic from existing gateway data.
• The updateGateway fallback URL ("/gateways/" when gatewayId is undefined) won't be reached in current code, but it's a footgun if the logic shifts. A comment or assertion would help.