feat(phase-6): WS3+WS4+WS6 — Analytics, API Tiers, AGNTCY Compliance

WS3 — Advanced Analytics Dashboard:
- DB migration: analytics_events table (tenant_id, date, metric_type, count)
- AnalyticsService: recordEvent (fire-and-forget), getTokenTrend, getAgentActivity, getAgentUsageSummary
- Analytics hooks in OAuth2Service (token_issued) and AgentService (agent_registered/deactivated)
- AnalyticsController + routes/analytics.ts (gated by ANALYTICS_ENABLED flag)
- Portal: TokenTrendChart (recharts LineChart), AgentHeatmap (recharts heatmap), /analytics page

WS4 — API Gateway Tiers:
- DB migration: tenant_tiers table; src/config/tiers.ts (free/pro/enterprise limits)
- TierService: getStatus, initiateUpgrade (Stripe), applyUpgrade; TierLimitError in errors.ts
- tierEnforcement middleware (Redis-backed daily call/token counters; TIER_ENFORCEMENT flag)
- Agent count enforcement in AgentService.create()
- Stripe webhook updated to call TierService.applyUpgrade() on checkout.session.completed
- TierController + routes/tiers.ts; Portal: /settings/tier page with upgrade flow

WS6 — AGNTCY Compliance Certification:
- ComplianceService: generateReport() (Redis-cached 5 min), exportAgentCards()
- Compliance sections: agent-identity (DID + credential expiry checks), audit-trail (Merkle chain)
- ComplianceController updated with getComplianceReport, exportAgentCards handlers
- routes/compliance.ts: new AGNTCY routes (gated by COMPLIANCE_ENABLED flag); SOC2 routes unaffected

QA:
- 28 new unit tests: AnalyticsService (8), TierService (9), ComplianceService (11) — all pass
- 673 total unit tests passing; 0 TypeScript errors across API and portal
- AGNTCY conformance test suite at tests/agntcy-conformance/ (4 protocol tests)
- Portal builds cleanly: 9 routes including /analytics and /settings/tier
- Feature flags verified: ANALYTICS_ENABLED, TIER_ENFORCEMENT, COMPLIANCE_ENABLED

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

portal/components/charts/TokenTrendChart.tsx

@@ -0,0 +1,99 @@
+'use client';
+
+/**
+ * TokenTrendChart — Recharts LineChart showing daily token issuance counts.
+ *
+ * This component is designed to be lazy-loaded via `next/dynamic`. Do NOT
+ * import it directly from a page; use dynamic(() => import('./TokenTrendChart'))
+ * so that recharts stays out of the main bundle.
+ *
+ * @module components/charts/TokenTrendChart
+ */
+
+import React from 'react';
+import {
+  LineChart,
+  Line,
+  XAxis,
+  YAxis,
+  CartesianGrid,
+  Tooltip,
+  ResponsiveContainer,
+} from 'recharts';
+
+/** A single data point for the token trend line chart. */
+export interface TokenTrendDataPoint {
+  /** ISO 8601 date string (e.g. "2026-03-01"). */
+  date: string;
+  /** Number of tokens issued on this date. */
+  count: number;
+}
+
+/** Props for the TokenTrendChart component. */
+export interface TokenTrendChartProps {
+  /** Array of daily token issuance data points, sorted ascending by date. */
+  data: TokenTrendDataPoint[];
+}
+
+/**
+ * Formats an ISO date string as a short label (e.g. "Mar 1").
+ *
+ * @param dateStr - ISO 8601 date string
+ * @returns Formatted short date label
+ */
+function formatDateLabel(dateStr: string): string {
+  const d = new Date(dateStr);
+  return d.toLocaleDateString('en-US', { month: 'short', day: 'numeric' });
+}
+
+/**
+ * Renders a responsive line chart of daily token issuance counts using recharts.
+ *
+ * @param props - TokenTrendChartProps
+ * @returns JSX element
+ */
+export default function TokenTrendChart({
+  data,
+}: TokenTrendChartProps): React.ReactElement {
+  return (
+    <ResponsiveContainer width="100%" height={300}>
+      <LineChart
+        data={data}
+        margin={{ top: 8, right: 16, left: 0, bottom: 8 }}
+      >
+        <CartesianGrid strokeDasharray="3 3" stroke="#e2e8f0" />
+        <XAxis
+          dataKey="date"
+          tickFormatter={formatDateLabel}
+          tick={{ fontSize: 12, fill: '#64748b' }}
+          tickLine={false}
+          axisLine={{ stroke: '#cbd5e1' }}
+          interval="preserveStartEnd"
+        />
+        <YAxis
+          tick={{ fontSize: 12, fill: '#64748b' }}
+          tickLine={false}
+          axisLine={false}
+          allowDecimals={false}
+        />
+        <Tooltip
+          formatter={(value: number) => [value.toLocaleString(), 'Tokens issued']}
+          labelFormatter={(label: string) => formatDateLabel(label)}
+          contentStyle={{
+            borderRadius: '8px',
+            border: '1px solid #e2e8f0',
+            fontSize: '13px',
+          }}
+        />
+        <Line
+          type="monotone"
+          dataKey="count"
+          stroke="#6366f1"
+          strokeWidth={2}
+          dot={false}
+          activeDot={{ r: 4, fill: '#6366f1' }}
+        />
+      </LineChart>
+    </ResponsiveContainer>
+  );
+}