feat(BA-2806): Implement WebSocket connectionParams to HTTP headers conversion

[HyeockJinKim]

resolves #6378 (BA-2806)

Checklist: (if applicable)

• Milestone metadata specifying the target backport version
• Mention to the original issue
• Installer updates including:
  • Fixtures for db schema changes
  • New mandatory config options
• Update of end-to-end CLI integration tests in ai.backend.test
• API server-client counterparts (e.g., manager API -> client SDK)
• Test case(s) to:
  • Demonstrate the difference of before/after
  • Demonstrate the flow of abstract/conceptual models with a concrete implementation
• Documentation
  • Contents in the docs directory
  • docstrings in public interfaces and type annotations

[Copilot]

Pull Request Overview

This PR implements WebSocket connectionParams to HTTP headers conversion for the GraphQL gateway, enabling authentication parameters sent via WebSocket connection_init to be forwarded as HTTP headers in federation requests to subgraphs.

Key Changes:

• Added a custom plugin (useConnectionParamsToHeadersPlugin) that intercepts subgraph execution to inject WebSocket connectionParams as HTTP headers
• Updated propagateHeaders.fromClientToSubgraphs to use context-based headers instead of request headers
• Configured WebSocket subscriptions with connectionParams that map context headers

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
configs/graphql/supergraph.yaml	Removed legacy Apollo Router supergraph configuration
configs/graphql/router.yaml	Removed legacy Apollo Router configuration
configs/graphql/gateway.config.ts	Implemented WebSocket connectionParams to headers conversion plugin and updated gateway configuration

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[Copilot]

The execRequest parameter uses any type, which bypasses TypeScript's type safety. Consider using a proper type from the gateway library or defining an appropriate interface for the execution request.

Suggested change

	const wrappedExecutor = async (execRequest: any) => {
	interface ExecutorRequest {
	context: {
	headers?: Record<string, string>;
	[key: string]: any;
	};
	extensions?: Record<string, any>;
	[key: string]: any;
	}
	const wrappedExecutor = async (execRequest: ExecutorRequest) => {

[Copilot]

Mutating the original headers object with delete could cause unintended side effects. Create a copy of the headers object before modification: const reqHeaders = { ...(execRequest.context.headers || {}) }; followed by delete reqHeaders['content-length'];

Suggested change

	let reqHeaders = execRequest.context.headers || {};
	const reqHeaders = { ...(execRequest.context.headers || {}) };

[Copilot]

The string literal '{context.headers.authorization}' appears to be a template string but may not be processed as expected. Add a comment explaining the expected format or mechanism by which this placeholder is resolved at runtime.

Suggested change

	connectionParams: {
	token: '{context.headers.authorization}'
	}
	// Set connectionParams as a function to dynamically inject the Authorization header at runtime
	connectionParams: (context: any) => ({
	token: context.headers?.authorization
	})