Issue list update

[jmid]

This PR

• adds the long-standing threadomain issue
• marks the Out_channel regression issue as fixed

[jmid]

CI summary:

• Cygwin trunk failed during flexlink configure #439
• MinGW bytecode 5.2 triggered an infinite loop in threadomain #203

Out of 35 workflows, 2 failed - both with genuine issues.

[jmid]

CI summary for merge to main:

• Cygwin trunk failed during flexlink configure #439

Out of 36 workflows, 1 failed with a genuine issue