[Bug] Unable to save custom MCP headers from admin panel #56

Description

Unable to save custom headers configured through the admin panel for MCP connections.

The admin panel generates the following structure:

type: streamable-http
url: https://example.com/api/mcp
headers:
  - key: Authorization
    value: Bearer {{API_KEY}}
    valueType: string

However, the configuration is not accepted/saved correctly.

Expected behavior

Custom headers added in the admin panel should be serialized into valid YAML and correctly loaded by the backend.

Expected result:

• headers are persisted
• MCP connection works with Authorization header
• generated YAML matches the expected schema

Actual behavior

Headers cannot be saved or are ignored after saving.

Possible issue:

• headers may be serialized in an invalid YAML format
• backend may expect an object instead of an array
• valueType may not be supported by the parser/schema

Steps to reproduce

1. Open admin panel

2. Create/edit MCP configuration

3. Add custom header:

   • key: Authorization
   • value: Bearer {{API_KEY}}

4. Save configuration

5. Observe that headers are not persisted or configuration becomes invalid

Generated config

type: streamable-http
url: https://example.com/api/mcp
headers:
  - key: Authorization
    value: Bearer {{API_KEY}}
    valueType: string

Questions

• What is the expected YAML schema for headers?
• Should headers be an object instead?

Example alternative format:

headers:
  Authorization: Bearer {{API_KEY}}

• Is valueType supported?