fix(observer): stop panicking on transient OS state - #1916
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Under panic=abort, several transient conditions in the observer aborted the whole run, which ADR-004 forbids. The stat sampler skips a stale /proc/<pid>/stat sample after PID reuse instead of asserting, and parses cgroup cpu.max with a bounds-checked helper that returns an error rather than indexing past a truncated read. Descendant listing yields an empty iterator when a target process vanishes instead of unwrapping into a panic. The sample loop treats a procfs, cgroup, or wss read failure as best-effort, logging and skipping that component rather than killing the experiment.
…comm parse(/proc/<pid>/stat) sliced &contents[end_paren + 2..] on the routine per-process CPU-sampling path, assuming two bytes follow the comm's closing ')'. A read truncated at the ')' -- the same transient short-read this commit's sibling guards already defend against -- made that slice panic, aborting the whole run under panic=abort (ADR-004). Use a bounds-checked get() that returns Error::StatMalformed instead, and add a test driving truncated inputs.
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This was referenced Jul 21, 2026
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