fix: diagnose conditional Task waits

[georgepwall1991]

Summary

• diagnose null-conditional Task.Wait calls inside async code
• normalize ordinary member access and conditional member binding before the existing semantic checks
• preserve zero-timeout exclusions, including conditional task?.Wait(0) probes
• intentionally offer no conditional-access fix and update v1.27.195 metadata

Verification

• red: new conditional wait test expected 1 CC015 diagnostic and received 0
• green: focused CC015 suite passed 20/20
• Release build: 62 expected sample warnings, 0 errors
• full Release suite: 656/656 passed
• packed dependency-free CancelCop.Analyzer.1.27.195.nupkg with both analyzer DLLs
• touched-file whitespace check passed

Review

• self-review requested by repository owner; no Claude review used