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>

package.json

@@ -31,6 +31,11 @@
     "@hookform/resolvers": "^3.9.1",
     "@mantine/core": "^8.3.13",
     "@mantine/hooks": "^8.3.13",
+    "@nivo/bar": "^0.99.0",
+    "@nivo/core": "^0.99.0",
+    "@nivo/line": "^0.99.0",
+    "@nivo/pie": "^0.99.0",
+    "@nivo/scatterplot": "^0.99.0",
     "@notionhq/client": "^2.3.0",
     "@prisma/client": "^6.19.2",
     "@radix-ui/react-alert-dialog": "^1.1.4",
@@ -50,6 +55,7 @@
     "@radix-ui/react-slot": "^1.1.1",
     "@radix-ui/react-switch": "^1.1.2",
     "@radix-ui/react-tabs": "^1.1.2",
+    "@radix-ui/react-toggle": "^1.1.10",
     "@radix-ui/react-tooltip": "^1.1.6",
     "@tailwindcss/postcss": "^4.1.18",
     "@tanstack/react-query": "^5.62.0",
@@ -85,7 +91,6 @@
     "react-hook-form": "^7.54.2",
     "react-leaflet": "^5.0.0",
     "react-phone-number-input": "^3.4.14",
-    "recharts": "^3.7.0",
     "sonner": "^2.0.7",
     "superjson": "^2.2.2",
     "tailwind-merge": "^3.4.0",