┌─────────────────────────────────────────────────────────┐
│  Manifest Layer (compile-time)                          │
│  Static TypeScript declarations in extensions/*/manifest│
├─────────────────────────────────────────────────────────┤
│  Registry Layer (app startup)                           │
│  ModuleRegistry lazy-loads manifests, resolves state    │
├─────────────────────────────────────────────────────────┤
│  Runtime Layer (per-organization)                       │
│  ModuleContext tracks active modules, contributions     │
└─────────────────────────────────────────────────────────┘

{id}/
├── manifest.ts                 # ModuleManifest declaration
├── index.ts                    # Public API (exports manifest)
├── types.ts                    # Extension-specific types
├── context/
│   └── {Id}Context.tsx         # Extension state provider
├── components/
│   ├── {Id}Layout.tsx          # Top-level layout/router
│   ├── pages/                  # Page components
│   └── widgets/                # Dashboard widgets
├── services/                   # Business logic
├── hooks/
│   ├── onActivate.ts           # Lifecycle: called after activation
│   ├── onDeactivate.ts         # Lifecycle: called before deactivation
│   └── onTenantSwitch.ts       # Lifecycle: org switch cleanup
└── handlers/
    └── on{Event}.ts            # EventBus handlers

dataCollections: ModuleDataCollection[] = [
  {
    name: string;              // Firestore collection name
    label: string;             // Human-readable label
    uninstallPolicy: 'retain' | 'archive' | 'delete';
    orgIdField?: string;       // Tenant scoping field (default: 'organizationId')
  }
]

{
  id: 'upcoming-deadlines',
  title: 'Upcoming Deadlines',
  description: 'Shows the next 5 grant deadlines',
  category: 'grants',
  componentPath: './components/widgets/UpcomingDeadlinesWidget',
  icon: 'CalendarClock',
  size: 'standard' | 'compact' | 'chart' | 'large',
  requiredPermissions?: ['VIEW_GRANT_CALENDAR']
}

{
  id: 'open-calendar',
  label: 'Open Grant Calendar',
  group: 'navigation' | 'create' | 'context' | 'ai',
  action: '/grant-calendar/calendar',
  keywords: ['calendar', 'deadlines'],
  permission: 'VIEW_GRANT_CALENDAR',
  priority: 10,
  section: 'Grant Calendar'
}

{
  name: 'check_upcoming_deadlines',
  description: 'Check upcoming grant deadlines within N days',
  requiredPermissions: ['VIEW_GRANT_CALENDAR'],
  handlerPath: './handlers/checkUpcomingDeadlines',
  creditCost: 1
}

AVAILABLE → TRIALING → ACTIVE ⇌ SUSPENDED → INACTIVE

organizations/{orgId}/moduleInstallations/{moduleId}
{
  id: string,                        // "{orgId}_{moduleId}"
  organizationId: string,
  moduleId: string,
  status: ModuleInstallStatus,
  installedVersion: string,
  installedAt: ISO 8601,
  installedBy: string,               // User ID
  trialEndsAt?: ISO 8601,
  stripeSubscriptionItemId?: string,
  settings: Record<string, unknown>,  // Module-specific config
  statusHistory: StatusChange[]       // Audit trail
}

User clicks "Install" in Marketplace
        │
        ├── Tier-included? → Direct activation (no Stripe)
        │
        ├── Trial requested? → startModuleTrial() via Cloud Function
        │                      → Create installation with trialEndsAt
        │
        └── Paid module? → addModuleToSubscription()
                           → Stripe Checkout session
                           → Webhook updates installation on payment

const MANIFEST_LOADERS = {
  'impact':               () => import('@/extensions/impact/manifest'),
  'grant-calendar':       () => import('@/extensions/grant-calendar/manifest'),
  'donor-wallet':         () => import('@/extensions/donor-wallet/manifest'),
  // ... all 12 extensions
};

interface ActiveExtensionContributions {
  widgets: Map<string, ExtensionWidgetContribution[]>;
  commands: Map<string, ExtensionCommandContribution[]>;
  agentTools: Map<string, ExtensionAgentToolContribution[]>;
  settingsPanels: Map<string, SettingsPanelEntry[]>;
}