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/README.md

@@ -199,13 +199,16 @@ client/
 │   │   │   ├── ClaudeAgentHubSettings.tsx   # Claude Code → Overview: CLAUDE_HOME, hook status, pricing
 │   │   │   ├── HomeDirSetting.tsx           # CLAUDE_HOME / CODEX_HOME editor (env-owned warning)
 │   │   │   ├── CodexHooksSettings.tsx       # Codex → Overview → Codex hooks card
+│   │   │   ├── ReportSettings.tsx           # Settings → Reports: scheduled report definitions, Run now, run history + downloads
 │   │   │   └── AntigravityHooksSettings.tsx # Antigravity → Antigravity hooks card
 │   │   └── workflows/      # Dashboard → Analytics → Workflow panels: own-pipeline stats + D3 analytics (11 files)
 │   │
 │   ├── pages/              # Route pages
-│   │   ├── Dashboard.tsx      # Monitor / Analytics / Health tabs
+│   │   ├── Dashboard.tsx      # Monitor / Analytics / Health tabs; Analytics' date range (Today/This week from Monday/This month from the 1st/7d/30d/90d/All/Custom, `?range=`, lib/dateRange.ts) narrows its headline, cost and token cards
+│   │   ├── QueryExplorer.tsx  # /query: filter sessions / events / agents, sort, page, export CSV/JSON (GET /api/query)
 │   │   ├── Sessions.tsx       # Filterable table; shows each session's real name (synced live from the transcript), falls back to the short ID
-│   │   ├── SessionDetail.tsx  # Agent tree + event timeline + Conversation tab (slash-command pills & output, inline rename markers)
+│   │   ├── SessionDetail.tsx  # Agent tree + event timeline + Conversation tab (slash-command pills & output, inline rename markers) + Replay tab (EventReplay) + Snapshot action
+│   │   ├── SnapshotView.tsx   # Read-only /snapshot/:token page over a frozen session payload
 │   │   ├── ActivityFeed.tsx  # Real-time event log; row click expands payload; Session btn navigates
 │   │   ├── Workflows.tsx      # Workflow analytics, rendered in Dashboard → Analytics → Workflow
 │   │   ├── Settings.tsx
@@ -501,6 +504,7 @@ function App() {
           <Route index element={<Dashboard />} />
           <Route path="sessions" element={<History />} />
           <Route path="sessions/:id" element={<SessionDetail />} />
+          <Route path="query" element={<QueryExplorer />} />
           {/* legacy path - the activity feed is now a tab on /sessions */}
           <Route path="activity" element={<Navigate to="/sessions?view=events" replace />} />
           <Route path="workflows" element={<Navigate to="/?tab=analytics&sub=workflow" replace />} />