feat(analysis): add trend charts to the Analysis page

The Analysis page only showed KPI numbers. Add two real time-series and render
them as dependency-free bar charts (matching components/chat/sparkline.tsx):

- backend: GET /api/analytics now returns `trends.patientsByMonth` (new patients
  per month over the last 6 months) and `trends.appointmentsByWeekday`
  (appointments per day for the current week), bucketed in JS from one query each.
- frontend: new components/analysis/bar-chart.tsx and two chart sections on the
  Analysis view (Patient growth, Appointments this week), with i18n keys.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/components/analysis/analysis-view.tsx

@@ -3,6 +3,7 @@
 import { type ReactNode, useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
 
+import { BarChart } from "@/components/analysis/bar-chart";
 import { Card } from "@/components/ui/card";
 import { type Analytics, getAnalytics } from "@/lib/analytics";
 
@@ -45,6 +46,27 @@ function Section({
   );
 }
 
+// A full-width section that frames a single chart in a card.
+function ChartSection({
+  title,
+  description,
+  children,
+}: {
+  title: string;
+  description: string;
+  children: ReactNode;
+}) {
+  return (
+    <section className="flex flex-col gap-3">
+      <div>
+        <h2 className="font-semibold text-lg tracking-tight">{title}</h2>
+        <p className="text-muted-foreground text-sm">{description}</p>
+      </div>
+      <Card className="p-5">{children}</Card>
+    </section>
+  );
+}
+
 export function AnalysisView() {
   const { t } = useTranslation();
   const [data, setData] = useState<Analytics | null>(null);
@@ -92,6 +114,16 @@ export function AnalysisView() {
         />
       </Section>
 
+      <ChartSection
+        description={t("analysis.charts.patientGrowthDescription")}
+        title={t("analysis.charts.patientGrowthTitle")}
+      >
+        <BarChart
+          data={data?.trends.patientsByMonth ?? []}
+          emptyLabel={t("analysis.charts.empty")}
+        />
+      </ChartSection>
+
       <Section
         description={t("analysis.appointments.description")}
         title={t("analysis.appointments.title")}
@@ -114,6 +146,16 @@ export function AnalysisView() {
         />
       </Section>
 
+      <ChartSection
+        description={t("analysis.charts.weeklyAppointmentsDescription")}
+        title={t("analysis.charts.weeklyAppointmentsTitle")}
+      >
+        <BarChart
+          data={data?.trends.appointmentsByWeekday ?? []}
+          emptyLabel={t("analysis.charts.empty")}
+        />
+      </ChartSection>
+
       <Section
         description={t("analysis.prescriptions.description")}
         title={t("analysis.prescriptions.title")}

frontend/components/analysis/bar-chart.tsx

@@ -0,0 +1,59 @@
+"use client";
+
+import type { TrendPoint } from "@/lib/analytics";
+import { cn } from "@/lib/utils";
+
+// A small dependency-free vertical bar chart (matches the spirit of
+// components/chat/sparkline.tsx). Bars scale to the series max; each shows its
+// value above and its label below. Themed with semantic tokens.
+export function BarChart({
+  data,
+  className,
+  emptyLabel,
+}: {
+  data: TrendPoint[];
+  className?: string;
+  emptyLabel: string;
+}) {
+  const max = Math.max(1, ...data.map((d) => d.count));
+  const hasData = data.some((d) => d.count > 0);
+
+  if (data.length === 0 || !hasData) {
+    return (
+      <div
+        className={cn(
+          "flex h-44 items-center justify-center text-muted-foreground text-sm",
+          className,
+        )}
+      >
+        {emptyLabel}
+      </div>
+    );
+  }
+
+  return (
+    <div className={cn("flex h-44 items-end gap-2 sm:gap-3", className)}>
+      {data.map((d, i) => {
+        const pct = (d.count / max) * 100;
+        return (
+          <div
+            className="flex h-full flex-1 flex-col items-center gap-1.5"
+            key={`${d.label}-${i}`}
+          >
+            <span className="font-medium text-foreground text-xs tabular-nums">
+              {d.count}
+            </span>
+            <div className="flex w-full flex-1 items-end">
+              <div
+                className="w-full rounded-t-md bg-primary/80 transition-colors hover:bg-primary"
+                style={{ height: `${Math.max(pct, d.count > 0 ? 4 : 0)}%` }}
+                title={`${d.label}: ${d.count}`}
+              />
+            </div>
+            <span className="text-muted-foreground text-xs">{d.label}</span>
+          </div>
+        );
+      })}
+    </div>
+  );
+}

frontend/lib/analytics.ts

@@ -2,6 +2,8 @@ import { apiFetch } from "@/lib/api-client";
 
 // Server-computed clinic analytics. Mirrors the backend `src/types/analytics.ts`.
 // All figures are aggregates over the active clinic's real data.
+export type TrendPoint = { label: string; count: number };
+
 export type Analytics = {
   patients: {
     total: number;
@@ -22,6 +24,10 @@ export type Analytics = {
     open: number;
     done: number;
   };
+  trends: {
+    patientsByMonth: TrendPoint[];
+    appointmentsByWeekday: TrendPoint[];
+  };
 };
 
 export function getAnalytics(): Promise<Analytics> {

frontend/lib/i18n/locales/en/translation.json

@@ -402,6 +402,13 @@
       "description": "Care-team workload",
       "open": "Open",
       "completed": "Completed"
+    },
+    "charts": {
+      "patientGrowthTitle": "Patient growth",
+      "patientGrowthDescription": "New patients per month over the last 6 months",
+      "weeklyAppointmentsTitle": "Appointments this week",
+      "weeklyAppointmentsDescription": "Bookings per day for the current week",
+      "empty": "No data yet"
     }
   },
   "activity": {