Improve connector reload authentication UX

[alexyaang]

Summary

• keep Azure access and refresh tokens in process memory instead of using the persistent native cache
• retain the selected connector namespace across reloads and show a focused sign-in state when authentication is missing
• return directly to the linked namespace catalog after browser sign-in
• update authentication, renderer, server regression coverage, and documentation

Validation

• 109 connector tests pass
• plugin validation passes
• marketplace generation produces no additional changes

[Copilot]

Pull request overview

Moves Azure authentication to process memory while preserving namespace selection across reloads.

Changes:

• Removes persistent Azure credential caching.
• Adds linked-namespace sign-in and catalog return flow.
• Updates regression tests and documentation.

Show a summary per file

File	Description
extensions/connector-namespaces/auth.mjs	Uses in-memory credentials and removes legacy artifacts.
extensions/connector-namespaces/auth.test.mjs	Tests in-memory authentication behavior.
extensions/connector-namespaces/package.json	Removes the persistence dependency.
extensions/connector-namespaces/renderer.mjs	Adds focused linked-namespace sign-in UI.
extensions/connector-namespaces/renderer.test.mjs	Covers rendering, redirects, and escaping.
extensions/connector-namespaces/server.mjs	Passes saved namespace context to the renderer.
extensions/connector-namespaces/server.test.mjs	Verifies reload sign-in messaging.
extensions/connector-namespaces/review-fixes.test.mjs	Guards against persistent-cache usage.
extensions/connector-namespaces/README.md	Documents process-memory authentication.
extensions/connector-namespaces/test/README.md	Updates smoke-test prerequisites.

Review details

• Files reviewed: 10/10 changed files
• Comments generated: 0
• Review effort level: Medium