feat(web): admin panel with session management (#89)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/web/src/app/(dashboard)/admin/page.tsx

@@ -0,0 +1,99 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { api } from '@/lib/api';
+
+interface SessionInfo {
+  id: string;
+  provider: string;
+  modelId: string;
+  createdAt: string;
+  promptCount: number;
+  channels: string[];
+  durationMs: number;
+}
+
+interface SessionsResponse {
+  sessions: SessionInfo[];
+  total: number;
+}
+
+export default function AdminPage(): React.ReactElement {
+  const [sessions, setSessions] = useState<SessionInfo[]>([]);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    api<SessionsResponse>('/api/sessions')
+      .then((res) => setSessions(res.sessions))
+      .catch(() => {})
+      .finally(() => setLoading(false));
+  }, []);
+
+  return (
+    <div className="mx-auto max-w-4xl space-y-8">
+      <h1 className="text-2xl font-semibold">Admin</h1>
+
+      {/* User Management placeholder */}
+      <section>
+        <h2 className="mb-4 text-lg font-medium text-text-secondary">User Management</h2>
+        <div className="rounded-lg border border-surface-border bg-surface-card p-6 text-center">
+          <p className="text-sm text-text-muted">
+            User management will be available when the admin API is implemented
+          </p>
+        </div>
+      </section>
+
+      {/* Active Agent Sessions */}
+      <section>
+        <h2 className="mb-4 text-lg font-medium text-text-secondary">Active Agent Sessions</h2>
+        {loading ? (
+          <p className="text-sm text-text-muted">Loading sessions...</p>
+        ) : sessions.length === 0 ? (
+          <div className="rounded-lg border border-surface-border bg-surface-card p-4">
+            <p className="text-sm text-text-muted">No active sessions</p>
+          </div>
+        ) : (
+          <div className="overflow-hidden rounded-lg border border-surface-border">
+            <table className="w-full">
+              <thead>
+                <tr className="border-b border-surface-border bg-surface-elevated text-left text-xs text-text-muted">
+                  <th className="px-4 py-2 font-medium">Session ID</th>
+                  <th className="px-4 py-2 font-medium">Provider</th>
+                  <th className="px-4 py-2 font-medium">Model</th>
+                  <th className="hidden px-4 py-2 font-medium md:table-cell">Prompts</th>
+                  <th className="hidden px-4 py-2 font-medium md:table-cell">Duration</th>
+                </tr>
+              </thead>
+              <tbody>
+                {sessions.map((s) => (
+                  <tr key={s.id} className="border-b border-surface-border last:border-b-0">
+                    <td className="max-w-[200px] truncate px-4 py-2 font-mono text-xs text-text-primary">
+                      {s.id}
+                    </td>
+                    <td className="px-4 py-2 text-xs text-text-muted">{s.provider}</td>
+                    <td className="px-4 py-2 text-xs text-text-muted">{s.modelId}</td>
+                    <td className="hidden px-4 py-2 text-xs text-text-muted md:table-cell">
+                      {s.promptCount}
+                    </td>
+                    <td className="hidden px-4 py-2 text-xs text-text-muted md:table-cell">
+                      {formatDuration(s.durationMs)}
+                    </td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </div>
+        )}
+      </section>
+    </div>
+  );
+}
+
+function formatDuration(ms: number): string {
+  const seconds = Math.floor(ms / 1000);
+  if (seconds < 60) return `${seconds}s`;
+  const minutes = Math.floor(seconds / 60);
+  if (minutes < 60) return `${minutes}m ${seconds % 60}s`;
+  const hours = Math.floor(minutes / 60);
+  return `${hours}h ${minutes % 60}m`;
+}

apps/web/src/components/layout/sidebar.tsx

@@ -15,6 +15,7 @@ const navItems: NavItem[] = [
   { label: 'Tasks', href: '/tasks', icon: '📋' },
   { label: 'Projects', href: '/projects', icon: '📁' },
   { label: 'Settings', href: '/settings', icon: '⚙️' },
+  { label: 'Admin', href: '/admin', icon: '🛡️' },
 ];
 
 export function Sidebar(): React.ReactElement {

docs/TASKS.md

@@ -34,8 +34,8 @@
 | P3-003 | done        | Phase 3   | Chat UI — conversations, messages, streaming                  | #84 | #28   |
 | P3-004 | done        | Phase 3   | Task management — list view + kanban board                    | #86 | #29   |
 | P3-005 | done        | Phase 3   | Project & mission views — dashboard + PRD viewer              | #87 | #30   |
-| P3-006 | in-progress | Phase 3   | Settings — provider config, profile, integrations             | —   | #31   |
+| P3-006 | done        | Phase 3   | Settings — provider config, profile, integrations             | #88 | #31   |
-| P3-007 | not-started | Phase 3   | Admin panel — user management, RBAC                           | —   | #32   |
+| P3-007 | in-progress | Phase 3   | Admin panel — user management, RBAC                           | —   | #32   |
 | P3-008 | not-started | Phase 3   | Verify Phase 3 — web dashboard functional E2E                 | —   | #33   |
 | P4-001 | not-started | Phase 4   | @mosaic/memory — preference + insight stores                  | —   | #34   |
 | P4-002 | not-started | Phase 4   | Semantic search — pgvector embeddings + search API            | —   | #35   |