feat: add dashboard charts — message trend, activity heatmap, top channels

services/frontend/src/components/dashboard/activity-heatmap.tsx

@@ -0,0 +1,62 @@
+"use client";
+
+import { GlassCard } from "@/components/glass/card";
+import { cn } from "@/lib/utils";
+
+const HOURS = Array.from({ length: 24 }, (_, i) => i);
+const DAYS = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"];
+
+interface ActivityHeatmapProps {
+  data?: Record<string, number>; // key: "day-hour", value: count
+}
+
+export function ActivityHeatmap({ data = {} }: ActivityHeatmapProps) {
+  const maxVal = Math.max(...Object.values(data), 1);
+
+  const getIntensity = (day: string, hour: number) => {
+    const val = data[`${day}-${hour}`] || 0;
+    const pct = val / maxVal;
+    if (pct === 0) return "bg-surface";
+    if (pct < 0.25) return "bg-primary/15";
+    if (pct < 0.5) return "bg-primary/30";
+    if (pct < 0.75) return "bg-primary/50";
+    return "bg-primary/70";
+  };
+
+  return (
+    <GlassCard variant="base">
+      <div className="flex items-center gap-2 mb-3">
+        <span className="text-xs font-semibold tracking-wide uppercase text-text-secondary">Activity</span>
+        <span className="text-[10px] text-text-secondary/40">hour × day</span>
+      </div>
+      <div className="overflow-x-auto">
+        <div className="flex gap-0.5 min-w-[400px]">
+          {/* Hour labels */}
+          <div className="flex flex-col gap-0.5 mr-1">
+            <div className="h-4" />
+            {DAYS.map((d) => (
+              <div key={d} className="h-3 flex items-center text-[8px] text-text-secondary/40 font-mono">{d}</div>
+            ))}
+          </div>
+          {/* Grid */}
+          <div className="flex gap-0.5">
+            {HOURS.map((hour) => (
+              <div key={hour} className="flex flex-col gap-0.5">
+                {DAYS.map((day) => (
+                  <div
+                    key={`${day}-${hour}`}
+                    className={cn("size-3 rounded-sm transition-colors", getIntensity(day, hour))}
+                    title={`${day} ${hour}:00 — ${data[`${day}-${hour}`] || 0}`}
+                  />
+                ))}
+                <div className="h-3 flex items-center justify-center text-[8px] text-text-secondary/30 font-mono">
+                  {hour % 4 === 0 ? hour : ""}
+                </div>
+              </div>
+            ))}
+          </div>
+        </div>
+      </div>
+    </GlassCard>
+  );
+}

services/frontend/src/components/dashboard/message-trend-chart.tsx

@@ -0,0 +1,48 @@
+"use client";
+
+import { GlassCard } from "@/components/glass/card";
+import { Area, AreaChart, ResponsiveContainer, Tooltip, XAxis, YAxis } from "recharts";
+
+interface MessageTrendChartProps {
+  data?: { date: string; messages: number; flagged: number }[];
+}
+
+export function MessageTrendChart({ data = [] }: MessageTrendChartProps) {
+  return (
+    <GlassCard variant="base">
+      <div className="flex items-center gap-2 mb-3">
+        <span className="text-xs font-semibold tracking-wide uppercase text-text-secondary">Message Trend</span>
+        <span className="text-[10px] text-text-secondary/40">7 days</span>
+      </div>
+      <div className="h-48">
+        <ResponsiveContainer width="100%" height="100%">
+          <AreaChart data={data}>
+            <defs>
+              <linearGradient id="trend-msg" x1="0" y1="0" x2="0" y2="1">
+                <stop offset="0%" stopColor="var(--color-primary)" stopOpacity={0.3} />
+                <stop offset="100%" stopColor="var(--color-primary)" stopOpacity={0} />
+              </linearGradient>
+              <linearGradient id="trend-flag" x1="0" y1="0" x2="0" y2="1">
+                <stop offset="0%" stopColor="var(--color-destructive)" stopOpacity={0.3} />
+                <stop offset="100%" stopColor="var(--color-destructive)" stopOpacity={0} />
+              </linearGradient>
+            </defs>
+            <XAxis dataKey="date" axisLine={false} tickLine={false} tick={{ fill: "oklch(0.55 0.02 245)", fontSize: 10 }} />
+            <YAxis axisLine={false} tickLine={false} tick={{ fill: "oklch(0.55 0.02 245)", fontSize: 10 }} />
+            <Tooltip
+              contentStyle={{
+                background: "oklch(0.11 0.02 245 / 0.9)",
+                border: "1px solid oklch(1 0 0 / 0.08)",
+                borderRadius: 8,
+                fontSize: 12,
+                color: "oklch(0.93 0.01 245)",
+              }}
+            />
+            <Area type="monotone" dataKey="messages" stroke="var(--color-primary)" strokeWidth={2} fill="url(#trend-msg)" />
+            <Area type="monotone" dataKey="flagged" stroke="var(--color-destructive)" strokeWidth={1.5} fill="url(#trend-flag)" />
+          </AreaChart>
+        </ResponsiveContainer>
+      </div>
+    </GlassCard>
+  );
+}

services/frontend/src/components/dashboard/top-channels-chart.tsx

@@ -0,0 +1,36 @@
+"use client";
+
+import { GlassCard } from "@/components/glass/card";
+import { Bar, BarChart, ResponsiveContainer, Tooltip, XAxis, YAxis } from "recharts";
+
+interface TopChannelsChartProps {
+  data?: { name: string; count: number }[];
+}
+
+export function TopChannelsChart({ data = [] }: TopChannelsChartProps) {
+  return (
+    <GlassCard variant="base">
+      <div className="flex items-center gap-2 mb-3">
+        <span className="text-xs font-semibold tracking-wide uppercase text-text-secondary">Top Channels</span>
+      </div>
+      <div className="h-48">
+        <ResponsiveContainer width="100%" height="100%">
+          <BarChart data={data} layout="vertical">
+            <XAxis type="number" axisLine={false} tickLine={false} tick={{ fill: "oklch(0.55 0.02 245)", fontSize: 10 }} />
+            <YAxis type="category" dataKey="name" axisLine={false} tickLine={false} tick={{ fill: "oklch(0.55 0.02 245)", fontSize: 10 }} width={80} />
+            <Tooltip
+              contentStyle={{
+                background: "oklch(0.11 0.02 245 / 0.9)",
+                border: "1px solid oklch(1 0 0 / 0.08)",
+                borderRadius: 8,
+                fontSize: 12,
+                color: "oklch(0.93 0.01 245)",
+              }}
+            />
+            <Bar dataKey="count" fill="var(--color-primary)" radius={[0, 4, 4, 0]} />
+          </BarChart>
+        </ResponsiveContainer>
+      </div>
+    </GlassCard>
+  );
+}