Drop pin-baselines.mjs: pinning is a once-per-phase paste and the
script hard-coded this phase's iteration-log row, so every later phase
would edit by hand anyway. Replace three hand-rolled argv parsers with
node:util parseArgs. Read machine facts from node:os instead of eight
subprocess probes (hw.model keeps its sysctl call). Track fixture bytes
with a running counter instead of re-walking the tree per file. Delete
the hover proxy that measured an argv the dock never spawns, plus
unused exports (ensureDir, assertAbsolute, GENERATED_FIXTURE_DIR).
Fixture output is byte-identical for the same seed (verified by full
tree diff against the pre-refactor generator) and all harness metrics
reproduce within run-to-run noise.
Scripted isolated-HOME measurements for session parse, incremental
append, period switch, CLI cold start, and RSS. Extends the #1164
timings.csv shape without touching parser, cache, or UI hot paths.
