Add conformance scenario: progress notification edge cases

[elang2]

The existing tools-call-with-progress scenario in tools.ts validates basic progress notification delivery. However, several spec requirements lack dedicated validation:

• Progress values MUST be non-decreasing across notifications for the same token
• If total is provided, it SHOULD remain consistent or increase
• progress SHOULD NOT exceed total
• Progress notifications MUST reference the correct progressToken
• No progress notifications should be sent when no progressToken was provided in the request
• Progress notifications MUST cease after the request completes

I'll submit a PR adding a standalone progress-notifications scenario covering these edge cases.