Add optional cloud agent delegation for LSP requests

[Copilot]

Adds abstraction layer for delegating LSP requests (completion, hover, definition) to cloud-based code intelligence services with automatic fallback to local LSP servers.

Changes

• Cloud agent interface (server/src/cloud/agent.ts)

  • ICloudAgent interface with HTTP implementation
  • Configurable via environment variables (CLOUD_AGENT_ENABLED, CLOUD_AGENT_ENDPOINT, CLOUD_AGENT_API_KEY)
  • Timeout handling and automatic fallback on errors

• LSP proxy delegation (server/src/lsp/proxy.ts)

  • Optional cloudAgent parameter added to constructor
  • Request handlers try cloud agent first, fall back to local LSP

  // Try cloud agent first if available
  if (this.cloudAgent) {
    const cloudResult = await this.cloudAgent.completion(params);
    if (cloudResult !== null) return cloudResult;
  }
  // Fall back to local LSP
  const client = await this.lsManager.getOrCreateClient(file.languageId);

• Configuration integration (server/src/index.ts)

  • Load cloud agent config from environment
  • Conditionally instantiate and pass to LSP proxy instances

Testing

• 11 unit tests covering enabled/disabled states, success/failure paths, and fallback behavior
• No security vulnerabilities (CodeQL)

Backward Compatibility

Cloud agent is optional and disabled by default. Zero impact on existing deployments.

Original prompt

Delegate: "Delegate to cloud agent"

Created from VS Code via the GitHub Pull Request extension.

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