Codex rollout files are append-only and the active ones run to hundreds
of MB, but any growth re-read the file from byte 0 because the cache
keyed only on mtime+size. The parser now records a restart point at every
task_started boundary — the byte offset plus the state the single-pass
decode carries across it — and a grown file with the same dev/ino picks
up from there.
The boundary sits at the task_started line itself, so the task it opens
is re-decoded from the tail; the entry stores how many calls were decoded
before that point so the resumed run starts from exactly those and cannot
double-count the open task. An unusable or absent snapshot falls back to
a full re-parse.
CODEX_CACHE_VERSION is deliberately not bumped: the new fields are
additive and absence-safe both ways, so a bump would discard a warm
cache for nothing.
Clear the per-directory Codex and Antigravity memo maps in the resident RSS
guard; document the single cache-dir rule (XDG_CACHE_HOME no longer
consulted, ledger migrated); stop output-overflow terminations from spending
the resident's unexpected-death budget.
