Simplify CreateConnection form UI

[kmcginnes]

Parent PRD

• Parent Simplify client-server relationship by removing proxy URL from connection config #1618

What to build

Update the CreateConnection form to remove proxy-related fields. Remove the "Public or Proxy Endpoint" text area, remove the "Using Proxy-Server" checkbox, and promote graphDbUrl ("Graph Connection URL") as the primary and only URL input field.

Type: HITL — requires review before completion.

Acceptance criteria

• "Public or Proxy Endpoint" field is removed from the form
• "Using Proxy-Server" checkbox is removed from the form
• graphDbUrl is the primary URL field, always visible, labeled clearly (e.g., "Graph Database URL")
• Form validation requires graphDbUrl
• Submitting the form produces a valid ConnectionConfig with graphDbUrl
• Tests verify the form renders without proxy-related fields
• Tests verify form submission produces correct data shape

Blocked by

• Blocked by Simplify ConnectionConfig — remove url and proxyConnection #1622

User stories addressed

• User story 1
• User story 2