Phase 3: Optimize & clean up — unified projects, account enhancements, new tenant fix

- Unify reserve_components + capital_projects into single projects model with
  full CRUD backend and new Projects page frontend
- Rewrite Capital Planning to read from unified projects/planning endpoint;
  add empty state directing users to Projects page when no planning items exist
- Add default designation to assessment groups with auto-set on first creation;
  units now require an assessment group (pre-populated with default)
- Add primary account designation (one per fund type) and balance adjustment
  via journal entries against equity offset accounts (3000/3100)
- Add computed investment fields (interest earned, maturity value, days remaining)
  with PostgreSQL date arithmetic fix for DATE - DATE integer result
- Restructure sidebar: investments in Accounts tab, Year-End under Reports,
  Planning section with Projects and Capital Planning
- Fix new tenant creation seeding unwanted default chart of accounts —
  new tenants now start with a blank slate

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

frontend/src/pages/units/UnitsPage.tsx

@@ -1,12 +1,12 @@
 import { useState } from 'react';
 import {
   Title, Table, Group, Button, Stack, TextInput, Modal,
-  NumberInput, Select, Badge, ActionIcon, Text, Loader, Center, Tooltip,
+  NumberInput, Select, Badge, ActionIcon, Text, Loader, Center, Tooltip, Alert,
 } from '@mantine/core';
 import { useForm } from '@mantine/form';
 import { useDisclosure } from '@mantine/hooks';
 import { notifications } from '@mantine/notifications';
-import { IconPlus, IconEdit, IconSearch, IconTrash } from '@tabler/icons-react';
+import { IconPlus, IconEdit, IconSearch, IconTrash, IconInfoCircle } from '@tabler/icons-react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import api from '../../services/api';
 
@@ -30,6 +30,7 @@ interface AssessmentGroup {
   name: string;
   regular_assessment: string;
   frequency: string;
+  is_default: boolean;
 }
 
 export function UnitsPage() {
@@ -49,13 +50,19 @@ export function UnitsPage() {
     queryFn: async () => { const { data } = await api.get('/assessment-groups'); return data; },
   });
 
+  const defaultGroup = assessmentGroups.find(g => g.is_default);
+  const hasGroups = assessmentGroups.length > 0;
+
   const form = useForm({
     initialValues: {
       unit_number: '', address_line1: '', city: '', state: '', zip_code: '',
       owner_name: '', owner_email: '', owner_phone: '', monthly_assessment: 0,
       assessment_group_id: '' as string | null,
     },
-    validate: { unit_number: (v) => (v.length > 0 ? null : 'Required') },
+    validate: {
+      unit_number: (v) => (v.length > 0 ? null : 'Required'),
+      assessment_group_id: (v) => (v && v.length > 0 ? null : 'Assessment group is required'),
+    },
   });
 
   const saveMutation = useMutation({
@@ -95,6 +102,17 @@ export function UnitsPage() {
     open();
   };
 
+  const handleNew = () => {
+    setEditing(null);
+    form.reset();
+    // Pre-populate with default group
+    if (defaultGroup) {
+      form.setFieldValue('assessment_group_id', defaultGroup.id);
+      form.setFieldValue('monthly_assessment', parseFloat(defaultGroup.regular_assessment || '0'));
+    }
+    open();
+  };
+
   const handleGroupChange = (groupId: string | null) => {
     form.setFieldValue('assessment_group_id', groupId);
     if (groupId) {
@@ -116,8 +134,21 @@ export function UnitsPage() {
     <Stack>
       <Group justify="space-between">
         <Title order={2}>Units / Homeowners</Title>
-        <Button leftSection={<IconPlus size={16} />} onClick={() => { setEditing(null); form.reset(); open(); }}>Add Unit</Button>
+        {hasGroups ? (
+          <Button leftSection={<IconPlus size={16} />} onClick={handleNew}>Add Unit</Button>
+        ) : (
+          <Tooltip label="Create an assessment group first">
+            <Button leftSection={<IconPlus size={16} />} disabled>Add Unit</Button>
+          </Tooltip>
+        )}
       </Group>
+
+      {!hasGroups && (
+        <Alert icon={<IconInfoCircle size={16} />} color="yellow" variant="light">
+          You must create at least one assessment group before adding units. Go to Assessment Groups to create one.
+        </Alert>
+      )}
+
       <TextInput placeholder="Search units..." leftSection={<IconSearch size={16} />} value={search} onChange={(e) => setSearch(e.currentTarget.value)} />
       <Table striped highlightOnHover>
         <Table.Thead>
@@ -182,14 +213,15 @@ export function UnitsPage() {
             <TextInput label="Owner Phone" {...form.getInputProps('owner_phone')} />
             <Select
               label="Assessment Group"
-              placeholder="Select a group (optional)"
+              description="Required — all units must belong to an assessment group"
+              required
               data={assessmentGroups.map(g => ({
                 value: g.id,
-                label: `${g.name} — $${parseFloat(g.regular_assessment || '0').toFixed(2)}/${g.frequency || 'mo'}`,
+                label: `${g.name}${g.is_default ? ' (Default)' : ''} — $${parseFloat(g.regular_assessment || '0').toFixed(2)}/${g.frequency || 'mo'}`,
               }))}
               value={form.values.assessment_group_id}
               onChange={handleGroupChange}
-              clearable
+              error={form.errors.assessment_group_id}
             />
             <NumberInput label="Monthly Assessment" prefix="$" decimalScale={2} min={0} {...form.getInputProps('monthly_assessment')} />
             <Button type="submit" loading={saveMutation.isPending}>{editing ? 'Update' : 'Create'}</Button>