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.Infrastructure/Services/SeedDataService.Accounts.cs

@@ -44,8 +44,11 @@ public partial class SeedDataService
         var accounts = new List<Account>
         {
             // ── ASSETS ────────────────────────────────────────────────────────
-            new Account { AccountNumber = "1000", Name = "Checking Account",          AccountType = AccountType.Asset,      AccountSubType = AccountSubType.Checking,            IsSystem = true,  IsActive = true, Description = "Primary business checking account",          CompanyId = company.Id, CreatedAt = now },
-            new Account { AccountNumber = "1010", Name = "Savings Account",           AccountType = AccountType.Asset,      AccountSubType = AccountSubType.Savings,             IsSystem = false, IsActive = true, Description = "Business savings account",                   CompanyId = company.Id, CreatedAt = now },
+            // Opening balances represent accumulated cash before the 12-month seeded history window.
+            // Without them, 12 months of seeded expenses outpace ~3 months of seeded revenue and
+            // the checking account shows a large negative — unrealistic for a demo.
+            new Account { AccountNumber = "1000", Name = "Checking Account",          AccountType = AccountType.Asset,      AccountSubType = AccountSubType.Checking,            IsSystem = true,  IsActive = true, Description = "Primary business checking account",          OpeningBalance = 75_000m, OpeningBalanceDate = now.AddYears(-1), CurrentBalance = 75_000m, CompanyId = company.Id, CreatedAt = now },
+            new Account { AccountNumber = "1010", Name = "Savings Account",           AccountType = AccountType.Asset,      AccountSubType = AccountSubType.Savings,             IsSystem = false, IsActive = true, Description = "Business savings account",                   OpeningBalance = 14_500m, OpeningBalanceDate = now.AddYears(-1), CurrentBalance = 14_500m, CompanyId = company.Id, CreatedAt = now },
             new Account { AccountNumber = "1100", Name = "Accounts Receivable",       AccountType = AccountType.Asset,      AccountSubType = AccountSubType.AccountsReceivable,  IsSystem = true,  IsActive = true, Description = "Amounts owed by customers for services",     CompanyId = company.Id, CreatedAt = now },
             new Account { AccountNumber = "1200", Name = "Inventory - Powder",        AccountType = AccountType.Asset,      AccountSubType = AccountSubType.Inventory,           IsSystem = false, IsActive = true, Description = "Powder coating materials in stock",          CompanyId = company.Id, CreatedAt = now },
             new Account { AccountNumber = "1210", Name = "Inventory - Consumables",   AccountType = AccountType.Asset,      AccountSubType = AccountSubType.Inventory,           IsSystem = false, IsActive = true, Description = "Masking, tape, and other consumables",       CompanyId = company.Id, CreatedAt = now },