feat(server): /metrics 可观测与日志上下文（F22）

- 新增 Prometheus 指标端点 /metrics（HTTP + DB + 作业统计）
- request.log 绑定 requestId/actorId，避免日志难追踪
- cron/pg-boss 作业增加 metrics 计数（runs/processed）
- 更新 env/runbook/README 与 v3 CSV 状态推进

server/src/observability/index.js

@@ -0,0 +1,6 @@
+const { initMetrics } = require("./metrics");
+
+module.exports = {
+  initMetrics,
+};
+

server/src/observability/metrics.js

@@ -0,0 +1,105 @@
+const client = require("prom-client");
+
+function resolveRouteLabel(request) {
+  const url = request?.routeOptions?.url;
+  if (typeof url === "string" && url.trim()) {
+    return url;
+  }
+
+  const routerPath = request?.routerPath;
+  if (typeof routerPath === "string" && routerPath.trim()) {
+    return routerPath;
+  }
+
+  const rawUrl = request?.raw?.url;
+  if (typeof rawUrl === "string" && rawUrl.trim()) {
+    return rawUrl.split("?")[0];
+  }
+
+  return "unknown";
+}
+
+function initMetrics(app) {
+  const registry = new client.Registry();
+
+  client.collectDefaultMetrics({
+    register: registry,
+  });
+
+  const httpRequestsTotal = new client.Counter({
+    name: "hyb_http_requests_total",
+    help: "Total number of HTTP requests",
+    labelNames: ["method", "route", "status_code"],
+    registers: [registry],
+  });
+
+  const httpRequestDurationSeconds = new client.Histogram({
+    name: "hyb_http_request_duration_seconds",
+    help: "HTTP request duration in seconds",
+    labelNames: ["method", "route", "status_code"],
+    buckets: [0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10],
+    registers: [registry],
+  });
+
+  const jobRunsTotal = new client.Counter({
+    name: "hyb_job_runs_total",
+    help: "Total number of background job runs",
+    labelNames: ["job", "driver", "outcome"],
+    registers: [registry],
+  });
+
+  const jobProcessedTotal = new client.Counter({
+    name: "hyb_job_processed_total",
+    help: "Total number of processed items per job",
+    labelNames: ["job", "driver", "kind"],
+    registers: [registry],
+  });
+
+  const dbReady = new client.Gauge({
+    name: "hyb_db_ready",
+    help: "Database readiness probe result (1=ready, 0=not ready)",
+    registers: [registry],
+  });
+
+  app.decorate("metrics", {
+    registry,
+    httpRequestsTotal,
+    httpRequestDurationSeconds,
+    jobRunsTotal,
+    jobProcessedTotal,
+    dbReady,
+  });
+
+  app.decorateRequest("metricsStart", null);
+
+  app.addHook("onRequest", async (request) => {
+    request.metricsStart = process.hrtime.bigint();
+  });
+
+  app.addHook("onResponse", async (request, reply) => {
+    const start = request.metricsStart;
+    if (typeof start !== "bigint") {
+      return;
+    }
+
+    const end = process.hrtime.bigint();
+    const durationSeconds = Number(end - start) / 1e9;
+
+    const method = request.method;
+    const route = resolveRouteLabel(request);
+    const statusCode = String(reply.statusCode);
+
+    httpRequestsTotal.inc({ method, route, status_code: statusCode });
+    httpRequestDurationSeconds.observe(
+      { method, route, status_code: statusCode },
+      durationSeconds,
+    );
+  });
+
+  return app.metrics;
+}
+
+module.exports = {
+  initMetrics,
+};
+