Read bounded stable prefixes through the installation file owner, preserve unknown header diagnostics, and propagate cancellation or incomplete cleanup. Share extent and identity validation with full artifact reads.
Validated with 269 focused tests, check:fast, and docs:check. Controlled Darwin file faults reproduce the original lost owner; real Ghidra and native Windows/Linux verification remain unperformed.
Refs #4676
Reject special files without blocking, cap the properties payload at 1 MiB before allocation, and verify descriptor extent and the selected name. Preserve Latin-1 data, selected symlinks, physical filesystem facts, completed observations and exact failed-close ownership.
Reuse the stable bounded reader for profile artifacts and consolidate Ghidra file failure projection. Distinguish missing-at-open from disappearance or read failure, and attribute typed prerequisite failures at the consuming operation.
Validation: 384 focused tests across 14 files, 42 seed/extension controls, 32 final metadata/profile/CLI controls, check:fast and docs:check. Controlled macOS file/process fixtures; no real Ghidra/JVM or Windows/Linux lifecycle verification.
Bounded FIFO reproduction: baseline direct and public doctor required external cleanup around 2.2s; candidate returned independently around 0.4/0.57s, all fixture groups verified empty. Warm normal doctor baseline/candidate: elapsed 1.211/1.230s, CPU 1.239/1.247s, sampled family RSS 524/524MB, reply tokens 3116/3116. No performance improvement claimed; true cold and whole-agent costs unmeasured.
Refs #4672
morluto