feat(web,coder): add analytics + results pages for token usage and run history

New /analytics route: token usage dashboard with aggregate summary,
per-session breakdown, context window stats, and per-category token
distribution. Data served from existing agent_sessions + tool_cost_stats.

New /results route: browsable archive of orchestrator flow runs and
arena battles. Two-tab layout (Analysis Runs / Arena Battles) using
existing API endpoints (no new backend).

Sidebar gains Results (ScrollText icon) and Token Analytics (BarChart3
icon) nav buttons above Settings.

apps/coder/src/routes/analytics.ts

@@ -0,0 +1,78 @@
+import type { FastifyInstance } from 'fastify';
+import type { Sql } from '../db.js';
+
+// token-analyzer-ui: aggregate token/cost analytics across all agent_sessions.
+// v1 — global view only (no per-project or per-user filtering).
+
+export interface AnalyticsSummary {
+  total_input_tokens: number;
+  total_output_tokens: number;
+  total_cost: number;
+  session_count: number;
+}
+
+export interface SessionAnalyticsRow {
+  session_id: string;
+  session_name: string;
+  total_input_tokens: number;
+  total_output_tokens: number;
+  total_cost: number;
+  last_active_at: string | null;
+}
+
+export interface TokenBreakdownAgg {
+  category: string;
+  total_tokens: number;
+}
+
+export function registerAnalyticsRoutes(app: FastifyInstance, sql: Sql): void {
+  // GET /api/analytics/summary — aggregate totals across all agent_sessions.
+  app.get('/api/analytics/summary', async () => {
+    const [row] = await sql<AnalyticsSummary[]>`
+      SELECT
+        COALESCE(SUM(a.input_tokens), 0)::BIGINT AS total_input_tokens,
+        COALESCE(SUM(a.output_tokens), 0)::BIGINT AS total_output_tokens,
+        COALESCE(SUM(a.cost), 0)::DOUBLE PRECISION AS total_cost,
+        COUNT(DISTINCT c.session_id)::INT AS session_count
+      FROM agent_sessions a
+      JOIN chats c ON c.id = a.chat_id
+    `;
+    return row ?? { total_input_tokens: 0, total_output_tokens: 0, total_cost: 0, session_count: 0 };
+  });
+
+  // GET /api/analytics/sessions — per-session token/cost breakdown.
+  app.get('/api/analytics/sessions', async () => {
+    const rows = await sql<SessionAnalyticsRow[]>`
+      SELECT
+        c.session_id AS session_id,
+        s.name AS session_name,
+        COALESCE(SUM(a.input_tokens), 0)::BIGINT AS total_input_tokens,
+        COALESCE(SUM(a.output_tokens), 0)::BIGINT AS total_output_tokens,
+        COALESCE(SUM(a.cost), 0)::DOUBLE PRECISION AS total_cost,
+        MAX(a.last_active_at) AS last_active_at
+      FROM agent_sessions a
+      JOIN chats c ON c.id = a.chat_id
+      JOIN sessions s ON s.id = c.session_id
+      GROUP BY c.session_id, s.name
+      ORDER BY MAX(a.last_active_at) DESC NULLS LAST
+    `;
+    return { sessions: rows };
+  });
+
+  // GET /api/analytics/token-breakdown — aggregate token_breakdown categories
+  // across all tasks that carry the JSONB field.
+  app.get('/api/analytics/token-breakdown', async () => {
+    const rows = await sql<{ category: string; total_tokens: number }[]>`
+      SELECT
+        key AS category,
+        SUM((value->>0)::BIGINT)::BIGINT AS total_tokens
+      FROM tasks,
+      LATERAL jsonb_each(token_breakdown)
+      WHERE token_breakdown IS NOT NULL
+        AND jsonb_typeof(token_breakdown) = 'object'
+      GROUP BY key
+      ORDER BY total_tokens DESC
+    `;
+    return { categories: rows };
+  });
+}