Phase G: Add Budgeting and Year-End Close

Budgeting:
- Budget + BudgetLine entities with Jan–Dec monthly columns per GL account
- BudgetsController: Index, Create, Edit, SetDefault, Copy, Delete
- Copy action rolls a budget forward to a new fiscal year
- Budget vs. Actual report (BudgetVsActual): compares monthly budget amounts to
  real P&L by calling GetProfitAndLossAsync once per month; variance shown as
  favorable/unfavorable; year + budget selectors in header
- Views: Budgets/Index, Create, Edit with inline annual totals via budget-edit.js
- Nav link + report card on Landing

Year-End Close:
- YearEndClose entity records each closed year + JE reference for audit trail
- AccountsController.YearEndClose GET (history + form) + CloseYear POST
- Close zeroes all Revenue and Expense/COGS account balances into Retained Earnings
  via IAccountBalanceService and posts a supporting JE dated Dec 31
- Idempotency: rejects attempt to close an already-closed year
- Pre-close checklist in view to guide the workflow
- Nav link under Finance

Migration AddBudgetsAndYearEndClose applied

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

src/PowderCoating.Infrastructure/Data/ApplicationDbContext.cs

@@ -343,6 +343,13 @@ public class ApplicationDbContext : IdentityDbContext<ApplicationUser>, IDataPro
     /// <summary>One record per asset per period for each depreciation posting; soft-delete only.</summary>
     public DbSet<FixedAssetDepreciationEntry> FixedAssetDepreciationEntries { get; set; }
 
+    /// <summary>Named annual budgets with monthly amounts per GL account; tenant-filtered with soft delete.</summary>
+    public DbSet<Budget> Budgets { get; set; }
+    /// <summary>One row per account per Budget; contains Jan–Dec decimal columns.</summary>
+    public DbSet<BudgetLine> BudgetLines { get; set; }
+    /// <summary>Audit trail of completed year-end closes; tenant-filtered with soft delete.</summary>
+    public DbSet<YearEndClose> YearEndCloses { get; set; }
+
     /// <summary>Credit notes received from vendors (returned goods, pricing disputes); tenant-filtered with soft delete.</summary>
     public DbSet<VendorCredit> VendorCredits { get; set; }
     /// <summary>Expense-reversal line items on a vendor credit; soft-delete only.</summary>
@@ -687,6 +694,27 @@ public class ApplicationDbContext : IdentityDbContext<ApplicationUser>, IDataPro
             .HasForeignKey(e => e.JournalEntryId)
             .OnDelete(DeleteBehavior.NoAction);
 
+        // Budgets: tenant-filtered; BudgetLines soft-delete only
+        modelBuilder.Entity<Budget>().HasQueryFilter(e =>
+            !e.IsDeleted && (IsPlatformAdmin || e.CompanyId == CurrentCompanyId));
+        modelBuilder.Entity<BudgetLine>().HasQueryFilter(e => !e.IsDeleted);
+
+        // BudgetLine → Account: Restrict delete so removing an account doesn't cascade into budget data
+        modelBuilder.Entity<BudgetLine>()
+            .HasOne(bl => bl.Account)
+            .WithMany()
+            .HasForeignKey(bl => bl.AccountId)
+            .OnDelete(DeleteBehavior.Restrict);
+
+        // YearEndClose: tenant-filtered; links to a specific JE
+        modelBuilder.Entity<YearEndClose>().HasQueryFilter(e =>
+            !e.IsDeleted && (IsPlatformAdmin || e.CompanyId == CurrentCompanyId));
+        modelBuilder.Entity<YearEndClose>()
+            .HasOne(y => y.JournalEntry)
+            .WithMany()
+            .HasForeignKey(y => y.JournalEntryId)
+            .OnDelete(DeleteBehavior.Restrict);
+
         // Vendor Credits: tenant-filtered; child rows soft-delete only
         modelBuilder.Entity<VendorCredit>().HasQueryFilter(e =>
             !e.IsDeleted && (IsPlatformAdmin || e.CompanyId == CurrentCompanyId));