[P1-3 cont.] Complete sync-over-async fixes across codebase

[cct08311github]

v8.1.13 fixed DoLogin. Remaining ~15 .Result/.Wait() calls cause ThreadPool starvation risk under load.

Locations:

• _WorkflowApiController.cs: 5x Request.RedirectCall(...).Result
• ApproveActivity.cs: 5x CallAPI(...).Result
• FrameworkServiceExtension.cs: DataInit(...).Wait()
• SessionExtension.cs: CommitAsync().Wait()

Fix: Convert to async/await. Keep sync wrappers marked [Obsolete] where public API.
Risk: Medium | Effort: 2-3 days