ci: increase BVT timeouts to 75 minutes

[aptend]

Summary

• increase compose BVT job timeouts from 60 to 75 minutes
• increase standalone multi-CN/proxy and pessimistic BVT job timeouts from 60 to 75 minutes
• increase TKE and coverage BVT step timeouts from 60 to 75 minutes
• keep shorter setup/launch and workload-specific timeout guards unchanged

Why

Recent hosted-runner slowdowns have stretched otherwise progressing BVT jobs beyond the 60-minute limit. A 75-minute ceiling provides headroom for transient runner variance while preserving bounded execution.

Same-SHA rerun evidence

The same MatrixOne commit (eb35456fdf05c64d9140a4cca72fdd15f47bd894) produced both outcomes in run 30005896526:

• attempt 1 was cancelled by the 60-minute job limit while BVT was still progressing; BVT had run for 55 minutes and completed 914 cases
• attempt 2 passed unchanged in 44m59s total, with BVT completing in 38m15s
• the rerun completed all scripts successfully, confirming that the first timeout was transient runner variance rather than a deterministic test hang

A scan of 194 recent instances of the same compose job also found 123 successful runs with a 43.9-minute median and 46.5-minute P90. Rare slow runners stretched otherwise progressing test cases by roughly 1.6x, which can exceed the current 60-minute ceiling. Raising the limit to 75 minutes covers this observed tail without making execution unbounded.

Validation

• git diff --check
• verified no timeout-minutes: 60 entries remain in .github