test: consolidate 18 test PRs into single PR with deduplication and bug fixes

[anandgupta42]

Consolidate 18 hourly test PRs (#515, #526, #527, #528, #530, #531, #532, #533, #534, #535, #536, #537, #538, #539, #540, #541, #542, #543) into a single well-reviewed PR.

Tasks:

• Merge all test branches
• Remove redundant/duplicate tests
• Fix bugs discovered in PR descriptions
• Fix typecheck errors
• Close original PRs