kernel-cases: thread cases that are slow by nature get 600 s

2822, 3952 and 4149 cut long modelled threads into filleted or revolved
bodies; each takes minutes on today's kernel, so they get timeout_s 600
instead of the default 180.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/kernel-cases/threads/2822-modelled-thread-in-filleted-cube/expected.json

@@ -27,5 +27,6 @@
    20,
    10
   ]
- }
+ },
+ "timeout_s": 600
 }

tests/kernel-cases/threads/3952-modelled-thread-in-blind-hole-of-revolved-ring/expected.json

@@ -19,5 +19,6 @@
    30,
    30
   ]
- }
+ },
+ "timeout_s": 600
 }

tests/kernel-cases/threads/4149-internal-thread-below-counterbore-filleted-rim/expected.json

@@ -22,5 +22,6 @@
    20,
    30
   ]
- }
+ },
+ "timeout_s": 600
 }