docs, logging: required endpoints should documented, logs should make them obvious

[justinmk3]

Problem

• If a request fails because it is blocked by the network, our logs don't always show the actual URL that failed.
• We don't have clear documentation about which endpoints are required for AWS Toolkit and Amazon Q to work.

see also: https://www.github.com/aws/aws-toolkit-vscode/issues/5753#issuecomment-2472184399

Solution

1. Ensure that log messages mention the URL that failed.
2. Document required endpoints. Partial list (requires investigation):
   • https://idetoolkits.amazonwebservices.com

     aws-toolkit-vscode/packages/core/src/shared/constants.ts

     Line 12 in 4235561

     export const endpointsFileUrl: string = 'https://idetoolkits.amazonwebservices.com/endpoints.json'

   • Amazon Q endpoints: https://docs.aws.amazon.com/general/latest/gr/amazonq.html
   • https://docs.aws.amazon.com/amazonq/latest/qdeveloper-ug/vpc-interface-endpoints.html
     • com.amazonaws.<region>.q
     • com.amazonaws.<region>.codewhisperer