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.

client/src/lib/dateRange.ts

@@ -0,0 +1,64 @@
+/**
+ * @file dateRange — the Analytics date range: the preset ids kept in `?range=`
+ * (today / this week from Monday / this month from the 1st / 7d / 30d / 90d /
+ * all / custom), and `rangeDates`, which turns a preset (or
+ * a custom from/to) into the local `YYYY-MM-DD` bounds sent as `from`/`to`.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+export const RANGE_PRESETS = [
+  "today",
+  "week",
+  "month",
+  "7d",
+  "30d",
+  "90d",
+  "all",
+  "custom",
+] as const;
+export type RangePreset = (typeof RANGE_PRESETS)[number];
+
+/** Local, inclusive bounds; an absent end is open. */
+export interface DateRange {
+  from?: string;
+  to?: string;
+}
+
+/** A `?range=` value, or `all` for anything else. */
+export function parsePreset(v: string | null): RangePreset {
+  return (RANGE_PRESETS as readonly string[]).includes(v ?? "") ? (v as RangePreset) : "all";
+}
+
+/** `d` as a local `YYYY-MM-DD`. */
+export function localDate(d: Date): string {
+  const p = (n: number) => String(n).padStart(2, "0");
+  return `${d.getFullYear()}-${p(d.getMonth() + 1)}-${p(d.getDate())}`;
+}
+
+/** The bounds of a preset: `7d` = today and the 6 days before it; `week`
+ *  starts on Monday, `month` on the 1st, both ending today. */
+export function rangeDates(
+  preset: RangePreset,
+  custom: DateRange = {},
+  today: Date = new Date()
+): DateRange {
+  if (preset === "all") return {};
+  if (preset === "custom") {
+    return { from: custom.from || undefined, to: custom.to || undefined };
+  }
+  const start = new Date(today);
+  if (preset === "week") start.setDate(today.getDate() - ((today.getDay() + 6) % 7));
+  else if (preset === "month") start.setDate(1);
+  else if (preset !== "today") start.setDate(today.getDate() - (parseInt(preset, 10) - 1));
+  return { from: localDate(start), to: localDate(today) };
+}
+
+/** Set `from`/`to` (and `tz_offset`, which reads them) on a query string. */
+export function applyRange(qs: URLSearchParams, range?: DateRange): URLSearchParams {
+  if (range?.from) qs.set("from", range.from);
+  if (range?.to) qs.set("to", range.to);
+  if ((range?.from || range?.to) && !qs.has("tz_offset")) {
+    qs.set("tz_offset", String(new Date().getTimezoneOffset()));
+  }
+  return qs;
+}