feat: UX enhancements, member limits, forecast fix, and menu cleanup (v2026.3.19)

- Onboarding wizard: add Reserve Account step between Operating and Assessments,
  redirect to Budget Planning on completion
- Dashboard: health score pending state shows clickable links to set up missing items
- Projects/Vendors: rich empty-state wizard screens with real-world examples and CTAs
- Investment Planning: auto-refresh AI recommendations when empty or stale (>30 days)
- Hide Invoices and Payments menus (see PARKING-LOT.md for re-enablement)
- Send welcome email via Resend when new members are added to a tenant
- Enforce 5-member limit for Starter/Standard/Professional plans (Enterprise unlimited)
- Cash flow forecast: only mark months as "Actual" when journal entries exist,
  fixing the issue where months without data showed as actuals
- Bump version to 2026.3.19

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/org-members/OrgMembersPage.tsx

@@ -214,6 +214,13 @@ export function OrgMembersPage() {
         As an organization administrator, you can add board members, property managers, and
         viewers to give them access to this tenant. Each member can log in with their own
         credentials and see the same financial data.
+        {currentOrg?.planLevel && !['enterprise'].includes(currentOrg.planLevel) && (
+          <Text size="sm" mt={6} fw={500}>
+            Your {currentOrg.planLevel === 'professional' ? 'Professional' : 'Starter'} plan
+            supports up to 5 user accounts ({activeMembers.length}/5 used).
+            {activeMembers.length >= 5 && ' Upgrade to Enterprise for unlimited members.'}
+          </Text>
+        )}
       </Alert>
 
       <Table striped highlightOnHover>