feat(#37-41): Add domains, ideas, relationships, agents, widgets schema

Schema additions for issues #37-41:

New models:
- Domain (#37): Life domains (work, marriage, homelab, etc.)
- Idea (#38): Brain dumps with pgvector embeddings
- Relationship (#39): Generic entity linking (blocks, depends_on)
- Agent (#40): ClawdBot agent tracking with metrics
- AgentSession (#40): Conversation session tracking
- WidgetDefinition (#41): HUD widget registry
- UserLayout (#41): Per-user dashboard configuration

Updated models:
- Task, Event, Project: Added domainId foreign key
- User, Workspace: Added new relations

New enums:
- IdeaStatus: CAPTURED, PROCESSING, ACTIONABLE, ARCHIVED, DISCARDED
- RelationshipType: BLOCKS, BLOCKED_BY, DEPENDS_ON, etc.
- AgentStatus: IDLE, WORKING, WAITING, ERROR, TERMINATED
- EntityType: Added IDEA, DOMAIN

Migration: 20260129182803_add_domains_ideas_agents_widgets

apps/web/src/components/auth/LoginButton.tsx

@@ -0,0 +1,19 @@
+"use client";
+
+import { Button } from "@mosaic/ui";
+
+const API_URL = process.env.NEXT_PUBLIC_API_URL || "http://localhost:3001";
+
+export function LoginButton() {
+  const handleLogin = () => {
+    // Redirect to the backend OIDC authentication endpoint
+    // BetterAuth will handle the OIDC flow and redirect back to the callback
+    window.location.assign(`${API_URL}/auth/callback/authentik`);
+  };
+
+  return (
+    <Button variant="primary" onClick={handleLogin} className="w-full">
+      Sign In with Authentik
+    </Button>
+  );
+}