feat: analytics parity — tool cost, date ranges, budgets, query explorer, replay, snapshots (v2.4.0)

Analytics parity phases 2–7 (docs/plans/analytics-parity/), built on
138e706 and ported onto v2.3.1:
- Cost by AI tool (?tool= on cost/analytics/stats/workflows, by_tool,
  Codex fast/priority and flex tiers, agenthub_cost_usd_total{tool,model})
- Date ranges (from/to) on cost/analytics/workflows; Analytics range select
  with Today / This week (Monday) / This month (1st) / 7d / 30d / 90d / All /
  Custom; workflow filters carried into workflow-stats.js (read worker)
- Budgets and cost alerts as alert rule types (alert_rules rebuilt without
  its rule_type CHECK), GET /api/budgets/status, rule preview, spend pace,
  status-bar budget chip; rules stay editable in place
- Query Explorer (/query, allowlisted sort, CSV/JSON export) and scheduled
  reports (report_definitions/report_runs, Settings → Reports)
- Session Replay tab and immutable snapshots (session_snapshots, /snapshot/:token)
- Remote Codex sync, push ingest with a hashed token, privacy redaction and
  ignored folders (Settings → Data), Cursor sessions (no cost)
- Read-only MCP server, statusline, Grafana/Prometheus files

Also: resizable sidebar, pet run/wave animations, the workspace home keeps a
half-typed prompt, and the pre-commit hook runs only the related tests for a
small commit.

server/lib/budgets.js

@@ -0,0 +1,118 @@
+/**
+ * @file Spend budgets. A budget is an alert rule of type `budget` (config:
+ * `period` day | week | month, `limit_usd`, `thresholds` in percent, optional
+ * `tool` and `lane` scope, `tz_offset` = the browser's getTimezoneOffset() so a
+ * period starts at the user's local midnight). This module computes a budget's
+ * spend in its current period — priced exactly like GET /api/pricing/cost, by
+ * the day the tokens were spent — the pace-based projection to the period's
+ * end, and the status list behind GET /api/budgets/status. Firing lives in
+ * `alerts.js`, once per threshold per period.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+const { stmts } = require("../db");
+const { calculateCost, dailyTokenRows, costWhere } = require("../routes/pricing");
+
+const PERIODS = ["day", "week", "month"];
+const DAY_MS = 86_400_000;
+
+const ymd = (ms) => new Date(ms).toISOString().slice(0, 10);
+
+/**
+ * The period containing `now`, in the user's local time.
+ * @param {"day"|"week"|"month"} period
+ * @param {number} now epoch ms
+ * @param {number} tzOffset minutes, as getTimezoneOffset() (UTC+7 → -420)
+ * @param {number} [back] periods before the current one (0 = current)
+ * @returns {{start: string, end: string, startUtc: string, days: number, elapsed: number}}
+ *   `start`/`end` local dates (inclusive), `startUtc` the start as an ISO
+ *   instant, `elapsed` the fraction of the period gone (1 for a past period).
+ */
+function periodBounds(period, now, tzOffset = 0, back = 0) {
+  const local = new Date(now - tzOffset * 60_000); // read with getUTC*
+  let startLocal;
+  let endLocal; // exclusive
+  if (period === "day") {
+    startLocal = Date.UTC(local.getUTCFullYear(), local.getUTCMonth(), local.getUTCDate() - back);
+    endLocal = startLocal + DAY_MS;
+  } else if (period === "week") {
+    const dow = (local.getUTCDay() + 6) % 7; // Monday = 0
+    startLocal = Date.UTC(
+      local.getUTCFullYear(),
+      local.getUTCMonth(),
+      local.getUTCDate() - dow - 7 * back
+    );
+    endLocal = startLocal + 7 * DAY_MS;
+  } else {
+    startLocal = Date.UTC(local.getUTCFullYear(), local.getUTCMonth() - back, 1);
+    endLocal = Date.UTC(local.getUTCFullYear(), local.getUTCMonth() - back + 1, 1);
+  }
+  const span = endLocal - startLocal;
+  return {
+    start: ymd(startLocal),
+    end: ymd(endLocal - DAY_MS),
+    startUtc: new Date(startLocal + tzOffset * 60_000).toISOString(),
+    days: Math.round(span / DAY_MS),
+    elapsed: back > 0 ? 1 : Math.min(1, Math.max(0, (local.getTime() - startLocal) / span)),
+  };
+}
+
+/**
+ * Spend of a budget config in one period (current by default).
+ * @returns {{period_start: string, period_end: string, spend: number,
+ *   projected: number, pct: number}}
+ */
+function budgetSpend(cfg, { now = Date.now(), back = 0, rules } = {}) {
+  const tz = Number.isFinite(cfg.tz_offset) ? cfg.tz_offset : 0;
+  const b = periodBounds(cfg.period, now, tz, back);
+  // A session that spent in the period was touched in it, so older ones are
+  // skipped before their hours are read.
+  const extra = [{ clause: "s.updated_at >= ?", params: [b.startUtc] }];
+  const scope = cfg.tool ? { where: "tool = ?", params: [cfg.tool] } : null;
+  const where = costWhere({ scope, lane: cfg.lane, extra });
+  const rows = dailyTokenRows(`${-tz} minutes`, where.whereClause, where.params).filter(
+    (r) => r.date >= b.start && r.date <= b.end
+  );
+  const spend = calculateCost(rows, rules || stmts.listPricing.all()).total_cost;
+  // The pace so far, carried to the period's end; at least an hour of pace so
+  // the first minutes of a period do not project a fortune.
+  const projected = spend / Math.max(b.elapsed, 1 / (b.days * 24));
+  const round = (n) => Math.round(n * 10000) / 10000;
+  return {
+    period_start: b.start,
+    period_end: b.end,
+    spend: round(spend),
+    projected: round(back > 0 ? spend : projected),
+    pct: cfg.limit_usd > 0 ? round((spend / cfg.limit_usd) * 100) : 0,
+  };
+}
+
+/** The thresholds a spend has reached, lowest first. */
+function crossed(cfg, pct) {
+  return [...cfg.thresholds].sort((a, b) => a - b).filter((t) => pct >= t);
+}
+
+/**
+ * Every enabled budget rule with its current-period spend.
+ * @returns {Array<object>} rule id/name/config + `budgetSpend` + `crossed`.
+ */
+function budgetStatus({ now = Date.now() } = {}) {
+  const rules = stmts.listPricing.all();
+  return stmts.listEnabledAlertRules
+    .all()
+    .filter((r) => r.rule_type === "budget")
+    .map((r) => {
+      let cfg;
+      try {
+        cfg = JSON.parse(r.config || "{}");
+      } catch {
+        return null;
+      }
+      if (!PERIODS.includes(cfg.period) || !(cfg.limit_usd > 0)) return null;
+      const s = budgetSpend(cfg, { now, rules });
+      return { id: r.id, name: r.name, config: cfg, ...s, crossed: crossed(cfg, s.pct) };
+    })
+    .filter(Boolean);
+}
+
+module.exports = { PERIODS, periodBounds, budgetSpend, budgetStatus, crossed };