feat(logger): update logger configuration to set log level to Fatal to eliminate IO lock contention

fix(redis): silence Redis internal logging and optimize connection pool settings to reduce mutex contention

feat(userlist): enhance user list component with avatar support and improved styling

test(load): add production-style load test script for WebSocket connections and Redis PubSub stress testing

chore(loadtest): create script to run load tests with pprof profiling for performance analysis

loadtest/run_with_pprof.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Simple helper to run k6 and capture pprof during peak load.
+# Usage:
+#   PPROF_BASE=http://localhost:8080/debug/pprof \
+#   K6_SCRIPT=loadtest/loadtest_prod.js \
+#   SLEEP_BEFORE=40 \
+#   CPU_SECONDS=30 \
+#   ./loadtest/run_with_pprof.sh
+
+PPROF_BASE="${PPROF_BASE:-http://localhost:8080/debug/pprof}"
+K6_SCRIPT="${K6_SCRIPT:-loadtest/loadtest_prod.js}"
+SLEEP_BEFORE="${SLEEP_BEFORE:-40}"
+CPU_SECONDS="${CPU_SECONDS:-30}"
+OUT_DIR="${OUT_DIR:-loadtest/pprof}"
+
+STAMP="$(date +%Y%m%d_%H%M%S)"
+RUN_DIR="${OUT_DIR}/${STAMP}"
+
+mkdir -p "${RUN_DIR}"
+
+echo "==> Starting k6: ${K6_SCRIPT}"
+k6 run "${K6_SCRIPT}" &
+K6_PID=$!
+
+echo "==> Waiting ${SLEEP_BEFORE}s before capturing pprof..."
+sleep "${SLEEP_BEFORE}"
+
+echo "==> Capturing profiles into ${RUN_DIR}"
+curl -sS "${PPROF_BASE}/profile?seconds=${CPU_SECONDS}" -o "${RUN_DIR}/cpu.pprof"
+curl -sS "${PPROF_BASE}/mutex" -o "${RUN_DIR}/mutex.pprof"
+curl -sS "${PPROF_BASE}/block" -o "${RUN_DIR}/block.pprof"
+curl -sS "${PPROF_BASE}/goroutine?debug=2" -o "${RUN_DIR}/goroutine.txt"
+
+echo "==> Waiting for k6 to finish (pid ${K6_PID})..."
+wait "${K6_PID}"
+
+echo "==> Done. Profiles saved in ${RUN_DIR}"
+echo "    Inspect with:"
+echo "      go tool pprof -top ${RUN_DIR}/cpu.pprof"
+echo "      go tool pprof -top ${RUN_DIR}/mutex.pprof"
+echo "      go tool pprof -top ${RUN_DIR}/block.pprof"