feat(security): receipt admin scripts + user git-ops (zero exceptions)

Wire the remaining shell egress through gstack-egress-lib.sh:

- gstack-gbrain-mcp-verify: both JSON-RPC probe POSTs (initialize +
  tools/list) receipted fail-closed via payload files (hash == wire
  bytes). A refused receipt lands in the NETWORK class — no send.
- gstack-security-dashboard / gstack-community-dashboard: the
  community-pulse GETs receipted fail-open (read-only stats must not
  break over an audit hiccup).
- gstack-gbrain-supabase-provision: api_call receipted fail-closed.
  Each retry attempt hands the helper a fresh copy of the body file
  (the helper consumes its payload). The receipt hashes the request
  body only — the PAT never reaches the ledger or any log. Refusal
  exits 8 without retrying.
- git-class sha256:null receipts, fail-open: gstack-artifacts-init
  (ls-remote, initial push, fetch/pull recovery, retry push),
  gstack-brain-restore (staging clone, existing-repo fetch),
  gstack-session-update (self-update pull).

gstack-team-init needs no wiring: every git clone in it is inside an
echoed instruction string, not an executed command.

The lib now self-locates with shell builtins only (no dirname), so
sourcing works under the whitelist-PATH test harnesses.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
(cherry picked from commit b8c5e2055b21ab72878b3e46f8047782ee65a11c)

bin/gstack-brain-restore

@@ -30,6 +30,10 @@ set -euo pipefail
 GSTACK_HOME="${GSTACK_HOME:-$HOME/.gstack}"
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 CONFIG_BIN="$SCRIPT_DIR/gstack-config"
+
+# Egress receipt helpers (_receipted_git): fail-open for user-directed
+# git ops against the user's own artifacts remote.
+. "$SCRIPT_DIR/gstack-egress-lib.sh"
 # v1.27.0.0+ canonical name; brain-remote is the legacy fallback during the
 # migration window. The migration script renames the file in place.
 if [ -f "$HOME/.gstack-artifacts-remote.txt" ]; then
@@ -78,7 +82,9 @@ STAGING=$(mktemp -d "${TMPDIR:-/tmp}/gstack-brain-restore.XXXXXX")
 trap 'rm -rf "$STAGING" 2>/dev/null' EXIT
 
 echo "Cloning $REMOTE_URL to staging..."
-if ! git clone --quiet "$REMOTE_URL" "$STAGING/repo" 2>/dev/null; then
+RESTORE_HOST="${REMOTE_URL#*://}"; RESTORE_HOST="${RESTORE_HOST#*@}"; RESTORE_HOST="${RESTORE_HOST%%[/:]*}"
+if ! _receipted_git open brain-restore "${RESTORE_HOST:-unknown}" brain-restore-clone "user ran gstack-brain-restore" \
+    bash -c 'git clone --quiet "$1" "$2" 2>/dev/null' _ "$REMOTE_URL" "$STAGING/repo"; then
   echo "Clone failed. Check:" >&2
   echo "  - URL is correct: $REMOTE_URL" >&2
   echo "  - Auth: gh auth status (github) / glab auth status (gitlab)" >&2
@@ -160,7 +166,8 @@ done
 # ---- move .git into place ----
 if [ -d "$GSTACK_HOME/.git" ]; then
   # Existing .git with matching remote — just fetch + fast-forward.
-  git -C "$GSTACK_HOME" fetch origin >/dev/null 2>&1 || true
+  _receipted_git open brain-restore "${RESTORE_HOST:-unknown}" brain-restore-fetch "user ran gstack-brain-restore" \
+    bash -c 'git -C "$1" fetch origin >/dev/null 2>&1' _ "$GSTACK_HOME" || true
 else
   mv "$STAGING/repo/.git" "$GSTACK_HOME/.git"
 fi