chore: add fixture-refresh helper script

scripts/refresh-user-fixture.sh wraps the TestRefreshFixtures
invocation: validates required env vars, warns on missing CF
credentials, runs the refresh, and re-runs the user parser tests
against the new fixture.

scripts/refresh-user-fixture.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+# Refresh testdata/html/user.html (and any other fixtures whose env vars are
+# set) by re-running TestRefreshFixtures against live FA with your cookies.
+#
+# Required:
+#   FA_A, FA_B            session cookies
+#   FA_TEST_USER          your FA username (lowercase, e.g. soxx-thefennec)
+#
+# Strongly recommended (otherwise Cloudflare will likely block the request):
+#   CF_CLEARANCE          cf_clearance cookie from the same browser session
+#   FA_UA                 the exact User-Agent that produced CF_CLEARANCE
+#
+# Usage:
+#   FA_A=... FA_B=... CF_CLEARANCE=... FA_UA="..." FA_TEST_USER=soxx-thefennec \
+#     ./scripts/refresh-user-fixture.sh
+#
+# Or export the vars in your shell first, then just run the script.
+
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+
+missing=()
+for var in FA_A FA_B FA_TEST_USER; do
+  if [[ -z "${!var:-}" ]]; then
+    missing+=("$var")
+  fi
+done
+if (( ${#missing[@]} )); then
+  echo "error: missing required env vars: ${missing[*]}" >&2
+  exit 1
+fi
+
+if [[ -z "${CF_CLEARANCE:-}" || -z "${FA_UA:-}" ]]; then
+  echo "warning: CF_CLEARANCE or FA_UA not set; the request will likely hit a Cloudflare challenge" >&2
+fi
+
+echo "refreshing fixtures for user=$FA_TEST_USER"
+go test -tags=fixtures -run TestRefreshFixtures -v ./...
+
+echo
+echo "re-running user parser tests against the new fixture"
+go test -run TestParseUser ./...