Quality-of-life enhancements: CSV import/export, opening balances, interest rates, mobile UX

- CSV import/export for Units, Projects, and Vendors with match-on-name/number upsert
- Cash Flow report toggle for Cash Only vs Cash + Investments
- Per-account and bulk opening balance setting with as-of date
- Interest rate field on normal accounts with estimated monthly/annual interest display
- Mobile sidebar auto-close on navigation
- Shared CSV parsing/export utility extracted to frontend/src/utils/csv.ts

DB migration needed for existing tenants:
  ALTER TABLE accounts ADD COLUMN IF NOT EXISTS interest_rate DECIMAL(6,4);

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

backend/src/modules/units/units.controller.ts

@@ -1,5 +1,6 @@
-import { Controller, Get, Post, Put, Delete, Body, Param, UseGuards } from '@nestjs/common';
+import { Controller, Get, Post, Put, Delete, Body, Param, Res, UseGuards } from '@nestjs/common';
 import { ApiTags, ApiBearerAuth } from '@nestjs/swagger';
+import { Response } from 'express';
 import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
 import { UnitsService } from './units.service';
 
@@ -13,9 +14,19 @@ export class UnitsController {
   @Get()
   findAll() { return this.unitsService.findAll(); }
 
+  @Get('export')
+  async exportCSV(@Res() res: Response) {
+    const csv = await this.unitsService.exportCSV();
+    res.set({ 'Content-Type': 'text/csv', 'Content-Disposition': 'attachment; filename="units.csv"' });
+    res.send(csv);
+  }
+
   @Get(':id')
   findOne(@Param('id') id: string) { return this.unitsService.findOne(id); }
 
+  @Post('import')
+  importCSV(@Body() rows: any[]) { return this.unitsService.importCSV(rows); }
+
   @Post()
   create(@Body() dto: any) { return this.unitsService.create(dto); }
 

backend/src/modules/units/units.service.ts

@@ -73,6 +73,90 @@ export class UnitsService {
     return rows[0];
   }
 
+  async exportCSV(): Promise<string> {
+    const rows = await this.tenant.query(
+      `SELECT unit_number, address_line1, city, state, zip_code, square_footage, lot_size,
+        owner_name, owner_email, owner_phone, is_rented, monthly_assessment, status
+       FROM units WHERE status != 'inactive' ORDER BY unit_number`,
+    );
+    const headers = ['unit_number', 'address_line1', 'city', 'state', 'zip_code', 'square_footage', 'lot_size',
+      'owner_name', 'owner_email', 'owner_phone', 'is_rented', 'monthly_assessment', 'status'];
+    const lines = [headers.join(',')];
+    for (const r of rows) {
+      lines.push(headers.map((h) => {
+        const v = r[h] ?? '';
+        const s = String(v);
+        return s.includes(',') || s.includes('"') ? `"${s.replace(/"/g, '""')}"` : s;
+      }).join(','));
+    }
+    return lines.join('\n');
+  }
+
+  async importCSV(rows: any[]) {
+    let created = 0, updated = 0;
+    const errors: string[] = [];
+
+    // Resolve default assessment group for new units
+    let defaultGroupId: string | null = null;
+    const defaultGroup = await this.tenant.query(
+      'SELECT id FROM assessment_groups WHERE is_default = true AND is_active = true LIMIT 1',
+    );
+    if (defaultGroup.length) defaultGroupId = defaultGroup[0].id;
+    else {
+      const anyGroup = await this.tenant.query('SELECT id FROM assessment_groups WHERE is_active = true LIMIT 1');
+      if (anyGroup.length) defaultGroupId = anyGroup[0].id;
+    }
+
+    for (let i = 0; i < rows.length; i++) {
+      const row = rows[i];
+      const unitNumber = (row.unit_number || '').trim();
+      if (!unitNumber) { errors.push(`Row ${i + 1}: missing unit_number`); continue; }
+
+      try {
+        const existing = await this.tenant.query('SELECT id FROM units WHERE unit_number = $1', [unitNumber]);
+        if (existing.length) {
+          await this.tenant.query(
+            `UPDATE units SET
+              address_line1 = COALESCE(NULLIF($2, ''), address_line1),
+              city = COALESCE(NULLIF($3, ''), city),
+              state = COALESCE(NULLIF($4, ''), state),
+              zip_code = COALESCE(NULLIF($5, ''), zip_code),
+              square_footage = COALESCE(NULLIF($6, '')::integer, square_footage),
+              lot_size = COALESCE(NULLIF($7, '')::decimal, lot_size),
+              owner_name = COALESCE(NULLIF($8, ''), owner_name),
+              owner_email = COALESCE(NULLIF($9, ''), owner_email),
+              owner_phone = COALESCE(NULLIF($10, ''), owner_phone),
+              is_rented = COALESCE(NULLIF($11, '')::boolean, is_rented),
+              monthly_assessment = COALESCE(NULLIF($12, '')::decimal, monthly_assessment),
+              status = COALESCE(NULLIF($13, ''), status),
+              updated_at = NOW()
+             WHERE id = $1`,
+            [existing[0].id, row.address_line1, row.city, row.state, row.zip_code,
+             row.square_footage, row.lot_size, row.owner_name, row.owner_email,
+             row.owner_phone, row.is_rented, row.monthly_assessment, row.status],
+          );
+          updated++;
+        } else {
+          if (!defaultGroupId) { errors.push(`Row ${i + 1}: no assessment group available for new unit`); continue; }
+          await this.tenant.query(
+            `INSERT INTO units (unit_number, address_line1, city, state, zip_code, square_footage, lot_size,
+              owner_name, owner_email, owner_phone, is_rented, monthly_assessment, status, assessment_group_id)
+             VALUES ($1, $2, $3, $4, $5, NULLIF($6, '')::integer, NULLIF($7, '')::decimal,
+              $8, $9, $10, COALESCE(NULLIF($11, '')::boolean, false), COALESCE(NULLIF($12, '')::decimal, 0), COALESCE(NULLIF($13, ''), 'active'), $14)`,
+            [unitNumber, row.address_line1 || null, row.city || null, row.state || null, row.zip_code || null,
+             row.square_footage || '', row.lot_size || '', row.owner_name || null, row.owner_email || null,
+             row.owner_phone || null, row.is_rented || '', row.monthly_assessment || '', row.status || '', defaultGroupId],
+          );
+          created++;
+        }
+      } catch (err: any) {
+        errors.push(`Row ${i + 1} (${unitNumber}): ${err.message}`);
+      }
+    }
+
+    return { imported: created + updated, created, updated, errors };
+  }
+
   async delete(id: string) {
     await this.findOne(id);