Capture true on-CPU profile of primary Ithaca PFE

User authorized a 60-second production on-CPU profile and concurrent CPU/load measurements on one current primary-role PFE, following capture tsk_sg8xnx2bxa and analysis tsk_dx96mv5x98. Prefer collect-linux or perf with JIT symbols; do not substitute managed wall-clock percentages for CPU shares. Separate substantial analysis into a linked task after verified collection. Preflight 2026-10-05T22:44Z: primary 4e68b8f07a9d / image b126bf974bf267794ce0af956092868c9595c865 (PR #2575/#2586), kernel 5.15.0-194-generic, perf_event_paranoid=4, kptr_restrict=1. perf not on PATH; collect-linux requires newer kernel user_events support, so investigate existing perf binaries and runtime symbol capabilities first. Host 357 GiB disk and 53 GiB available RAM. Constraints: no heap dump, restart, deployment, debugger, allocator changes, kernel setting changes, or package installation. A diagnostic binary copied into temporary capture storage is acceptable. User authorized collection, not production configuration changes. Acceptance: exact container/image/PID/start identity; actual 60-second kernel on-CPU samples and stated symbol/unwind coverage, concurrent CPU/load evidence, metadata and checksums, persistent remote backup and verified local download, unchanged PFE health and temporary diagnostic cleanup. If unavailable, record concrete prerequisite and do not mislabel a fallback wall-clock trace. Verified capture: perf-start 2026-10-05T22:46:50Z, end 22:47:51Z; sampled time span 59.99509s, image b126bf974, exact host PID 1646325/container start unchanged (2026-10-05T18:02:37.658900274Z), uptime approximately 4h44m12s at capture start. Standalone Ubuntu linux-tools-5.15.0-194=5.15.0-194.204 extracted under capture/tools, perf reports version5.15.209; no package installation or sysctl/runtime config change. Root process-scoped cpu-clock 99Hz with frame-pointer callchains captured 16,245 samples and reports zero lost. Contemporaneous .NET9.0.20 JIT/loader + default rundown trace65s completed; 124,213 native method ranges exported offline. 62.077s CPU-counter bracket measures 165.05 user + 8.18 system CPU seconds (2.791 cores), 43 process threads before capture. World-load reference is prior22:03Z heap, not a simultaneous online count; capture monitoring includes thread/RSS/CPU counters. Archive82,217,953 bytes, remote zip -T and local/remote SHA256 passed: ac1f483bcb0bc07069c8c46681d1b98ed72c3488fc0a47526f220c90a3d51f66. Inner perf.data/symbols.nettrace/perf-stacks.txt hashes passed. Persistent remote /home/mathias/pfe-cpu-20261005-2244/; local /home/mathias/Downloads/pfe-cpu-20261005-2244/. Exact before/after identity metadata match, Running=true, RestartCount=0, OOMKilled=false; temporary container directory removed and absence explicitly verified. Earlier heap-capture temporary directory absence also checked. Subsequent optional native symbol-report enrichment was blocked by intermittent SSH-agent authentication/timeouts; raw capture remains complete and verified. Analysis tsk_nka9m9gvx8.