feat(web): implement analytics dashboard for issue #30

AGENTS.md

@@ -34,7 +34,12 @@
 | `src/modules/events.js` | Event handler registration (wires modules to Discord events) |
 | `src/api/server.js` | Express API server setup (createApp, startServer, stopServer) |
 | `src/api/index.js` | API route mounting |
-| `src/api/routes/guilds.js` | Guild REST API endpoints (info, config, stats, members, moderation, actions) |
+| `src/api/routes/guilds.js` | Guild REST API endpoints (info, config, stats, members, moderation, analytics, actions) |
+| `web/src/components/dashboard/analytics-dashboard.tsx` | Analytics dashboard React component — charts, KPIs, date range controls |
+| `web/src/types/analytics.ts` | Shared analytics TypeScript contracts used by dashboard UI and analytics API responses |
+| `web/src/app/api/guilds/[guildId]/analytics/route.ts` | Next.js API route — proxies analytics requests to bot API with param allowlisting |
+| `web/src/lib/guild-selection.ts` | Guild selection state — localStorage persistence (`SELECTED_GUILD_KEY`) and cross-tab broadcast (`broadcastSelectedGuild`) |
+| `web/src/lib/bot-api.ts` | Bot API URL normalization — `getBotApiBaseUrl` for constructing stable v1 API endpoint |
 | `src/api/middleware/auth.js` | API authentication middleware |
 | `src/api/middleware/rateLimit.js` | Rate limiting middleware |
 | `src/utils/errors.js` | Error classes and handling utilities |

README.md

@@ -256,6 +256,7 @@ The `web/` directory contains a Next.js admin dashboard for managing Bill Bot th
 - **Discord OAuth2 Login** — Sign in with your Discord account via NextAuth.js
 - **Server Selector** — Choose from mutual guilds (servers where both you and the bot are present)
 - **Token Refresh** — Automatic Discord token refresh with graceful error handling
+- **Analytics Dashboard** — KPI cards, message/AI usage charts, channel activity filtering, and activity heatmaps
 - **Responsive UI** — Mobile-friendly layout with sidebar navigation and dark mode support
 
 ### Setup