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-security-dashboard

@@ -17,6 +17,9 @@ set -uo pipefail
 
 GSTACK_DIR="${GSTACK_DIR:-$(cd "$(dirname "$0")/.." && pwd)}"
 
+# Egress receipt helpers (_receipted_curl): fail-open for read-only stats.
+. "$GSTACK_DIR/bin/gstack-egress-lib.sh"
+
 # Source Supabase config
 if [ -z "${GSTACK_SUPABASE_URL:-}" ] && [ -f "$GSTACK_DIR/supabase/config.sh" ]; then
   . "$GSTACK_DIR/supabase/config.sh"
@@ -46,10 +49,11 @@ fi
 # surface are indistinguishable from good news.
 TMPBODY="$(mktemp)"
 trap 'rm -f "$TMPBODY"' EXIT
-HTTP_CODE="$(curl -s --max-time 15 -w '%{http_code}' -o "$TMPBODY" \
+SUPA_HOST="${SUPABASE_URL#*://}"; SUPA_HOST="${SUPA_HOST%%/*}"
+HTTP_CODE="$(_receipted_curl open security-dashboard "$SUPA_HOST" community-pulse-fetch "user-invoked dashboard" --no-payload \
+  curl -s --max-time 15 -w '%{http_code}' -o "$TMPBODY" \
   "${SUPABASE_URL}/functions/v1/community-pulse" \
-  -H "apikey: ${ANON_KEY}" \
-  2>/dev/null || true)"
+  -H "apikey: ${ANON_KEY}" || true)"
 # curl prints its own 000 before a non-zero exit — a `|| echo` here would
 # double it to "000000" in user-facing output. Normalize to the last 3 chars.
 HTTP_CODE="$(printf '%s' "$HTTP_CODE" | tr -d '[:space:]' | tail -c 3)"