Demo data realism + invoice resend via SMS on any status

Seed data fixes:
- Fix EF interceptor: no longer overwrites explicitly-set CreatedAt on Added
  entities — root cause of all "same month" chart issues
- Customer seeder: generates 15 customers/month from Jan → current month;
  keeps 10 commercial anchors in deterministic order for job seeder index map
- Invoice seeder: historical range bumped from 2→8 paid invoices/month so
  P&L shows consistent profit (~$5,200 collected vs ~$4,200 monthly expenses)
- Month -1 bumped to 7 paid invoices to stay above expenses
- Jobs: set UpdatedAt to historical event date so analytics don't need null fallback
- Analytics (ReportsController): use CompletedDate ?? UpdatedAt ?? CreatedAt for
  revenue chart grouping; fixes empty Revenue Trend charts on Overview/Revenue tabs
- SeedDataService: inject IAccountBalanceService; auto-recalculate account balances
  after seeding; patch checking/savings opening balances unconditionally on reset
- Customer list: sort by CompanyName ?? ContactLastName so individuals and
  commercial accounts interleave instead of appearing as two blocks

Invoice resend:
- ResendInvoice action now accepts sendEmail + sendSms parameters; SMS-only
  resend no longer requires an email address on file
- Ensures PublicViewToken exists before SMS so the view link is always valid
- canResend in Details view now allows Paid invoices (removed != Paid guard)
- Resend button shows channel-choice modal when customer has both email + SMS,
  direct SMS button when SMS only, or email button when email only
- New #resendChannelModal mirrors the Send channel modal but posts to ResendInvoice
- resendInvoice() JS updated to pass sendEmail/sendSms query params

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

src/PowderCoating.Web/Controllers/ReportsController.cs

@@ -146,12 +146,19 @@ public class ReportsController : Controller
             var momGrowth = revenueLastMonth > 0 ? Math.Round((revenueThisMonth - revenueLastMonth) / revenueLastMonth * 100, 1) : 0m;
 
             // === REVENUE ANALYTICS ===
-            // Pre-filter completed jobs by date range once for monthly calculations
-            var completedJobsInRange = completedJobs.Where(j => j.UpdatedAt >= startDate).ToList();
+            // CompletedDate is the authoritative "when the job finished" date.
+            // UpdatedAt is set by the EF interceptor only on Modified saves, so seeded/imported
+            // jobs may have UpdatedAt = null. Fall back to CreatedAt as a last resort.
+            static DateTime JobMonthDate(Job j) =>
+                j.CompletedDate ?? j.UpdatedAt ?? j.CreatedAt;
+
+            var completedJobsInRange = completedJobs
+                .Where(j => JobMonthDate(j) >= startDate)
+                .ToList();
 
             // Group by month for efficient monthly aggregations
             var jobsByMonth = completedJobsInRange
-                .GroupBy(j => new DateTime(j.UpdatedAt.Value.Year, j.UpdatedAt.Value.Month, 1))
+                .GroupBy(j => { var d = JobMonthDate(j); return new DateTime(d.Year, d.Month, 1); })
                 .ToDictionary(g => g.Key, g => g.ToList());
 
             // Monthly revenue trend