Observer platform overhaul: Nivo charts, round-type stats, UX improvements

Phase 1: Fix 6 backend data bugs in analytics.ts (roundName filtering,
unscored projects, criteria scores, activeRoundCount scoping, email
privacy leaks in juror consistency + workload)

Phase 2-3: Migrate all 9 chart components from Recharts to Nivo
(@nivo/bar, @nivo/line, @nivo/pie, @nivo/scatterplot) with shared brand
theme, scoreGradient colors, and STATUS_COLORS map. Fixes scatter plot
outlier coloring and pie chart label visibility bugs.

Phase 4: Add round-type-aware stats (getRoundTypeStats backend +
RoundTypeStatsCards component) showing appropriate metrics per round
type (intake/filtering/evaluation/submission/mentoring/live/deliberation).

Phase 5: UX improvements — Stage→Round terminology, clickable dashboard
round links, URL-based round selection (?round=), round type indicators
in selectors, accessible Toggle-based cross-round comparison, sortable
project table columns (title/score/evaluations), brand score colors on
dashboard bar chart with aria labels.

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

src/components/ui/toggle.tsx

@@ -0,0 +1,45 @@
+"use client"
+
+import * as React from "react"
+import * as TogglePrimitive from "@radix-ui/react-toggle"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@/lib/utils"
+
+const toggleVariants = cva(
+  "inline-flex items-center justify-center rounded-md text-sm font-medium ring-offset-background transition-colors hover:bg-muted hover:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50 data-[state=on]:bg-accent data-[state=on]:text-accent-foreground [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0 gap-2",
+  {
+    variants: {
+      variant: {
+        default: "bg-transparent",
+        outline:
+          "border border-input bg-transparent hover:bg-accent hover:text-accent-foreground",
+      },
+      size: {
+        default: "h-10 px-3 min-w-10",
+        sm: "h-9 px-2.5 min-w-9",
+        lg: "h-11 px-5 min-w-11",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+      size: "default",
+    },
+  }
+)
+
+const Toggle = React.forwardRef<
+  React.ElementRef<typeof TogglePrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof TogglePrimitive.Root> &
+    VariantProps<typeof toggleVariants>
+>(({ className, variant, size, ...props }, ref) => (
+  <TogglePrimitive.Root
+    ref={ref}
+    className={cn(toggleVariants({ variant, size, className }))}
+    {...props}
+  />
+))
+
+Toggle.displayName = TogglePrimitive.Root.displayName
+
+export { Toggle, toggleVariants }