fix: adversarial review fixes (Claude pass, 14 findings, 1 verified-live critical)

The fresh-context adversarial pass caught a live bug in this branch's own
performance fix: gstack-wtree exported GIT_INDEX_FILE BEFORE resolving the
real index path, so `git rev-parse --git-path index` returned the temp index
itself, the stat-cache copy self-copied and failed, and every invocation fell
back to the full re-hash — the fast path was dead code (verified with bash -x).
Resolution now happens before the export; measured 0.08s per call on this repo.

Also fixed: careful fails to an ASK (not silence) when its own helper file is
missing (same partial-install state freeze already defends against); the
--source label is sanitized inside the envelope lib (newline-stripped,
sentinel-defused, length-capped — it sits in trusted framing); the HIGH rm
tokenizer skips redirections/backgrounding/`--` (rm -rf / 2>/dev/null now
denies) and knows ${HOME}; user pattern lines starting with a dash work
(grep --); greptile bodies carry per-comment id headers inside the envelope so
multi-comment PRs stay attributable (ids verified against raw metadata, never
trusted in-body); the release-body tripwire fails CLOSED when its input files
are missing (separate-shell $$ reality); land 3.5b gets the same allow-paths
as ship; the "either side dirty" fallback leftover is gone from both grading
surfaces; the evidence pump races drain against error (EPIPE consumers can't
hang the wrapper); an unset HOME skips bookkeeping instead of creating a
literal ~ dir inside the repo; a write-failure log ends with a visible marker;
freeze expands a literal leading ~ in the boundary; review-log documents its
log-time binding window.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bin/gstack-wtree

@@ -29,11 +29,13 @@
 set -euo pipefail
 
 TOP=$(git rev-parse --show-toplevel 2>/dev/null) || exit 1
+# Resolve the REAL index path BEFORE exporting GIT_INDEX_FILE — with the env
+# var set, `git rev-parse --git-path index` returns the temp index itself and
+# the stat-cache seed silently self-copies into a dead fast path.
+REAL_INDEX=$(git -C "$TOP" rev-parse --git-path index 2>/dev/null || true)
 TMPIDX=$(mktemp "${TMPDIR:-/tmp}/gstack-wtree-XXXXXX")
 trap 'rm -f "$TMPIDX"' EXIT
 export GIT_INDEX_FILE="$TMPIDX"
-
-REAL_INDEX=$(git -C "$TOP" rev-parse --git-path index 2>/dev/null || true)
 # Resolve relative --git-path output against the repo root.
 case "$REAL_INDEX" in
   ""|/*) ;;