feat(auth): add per-organization PAT fallback

[rcappello]

This PR added deterministic per-organization PAT fallback to both clients while preserving global PAT discovery for backward compatibility. It also hardened credential cleanup and cancellation, completed cross-client localization, and prepared the VS Code and Visual Studio extensions for release 0.4.0.

Changes

Authentication and storage

• Added verified per-organization PAT slots and organization-aware authorization routing in both clients
• Merged global and per-organization roots with canonical, case-insensitive de-duplication
• Rolled back secrets when credential indexes could not be persisted
• Preserved failed cleanup entries for retry and surfaced incomplete credential deletion
• Prevented stale sign-in success, fallback cancellation races, and duplicate Visual Studio verification

User experience

• Added organization prompts, recent organization history, clipboard URL suggestions, verification feedback, and empty-state guidance
• Added the Add Azure DevOps organization command to VS Code and Visual Studio
• Added every new runtime key to the existing VS Code bundles and Visual Studio RESX catalogs

Release preparation

• Promoted both client changelogs and version sources to 0.4.0
• Documented GitHub Actions as the final VS Code clean install, test, bundle, and package gate because approved local proxy packages remain unavailable
• Updated release process instructions and translated the project constitution to English
• Anonymized Azure DevOps field evidence in the implementation plan

Related Issues

None

Notes

• Visual Studio Release build and localization parity checks passed.
• Local VS Code tests could not run after the corporate proxy blocked development-only packages and removed tsc; the release workflow remains the required clean-environment gate.
• No tag, publication, or release workflow was triggered by this PR.