Add 4 AI bookkeeping features

Feature 7: Bank Rec Auto-Match — AiSuggestMatches endpoint scores uncleared
transactions vs statement ending balance; AI Auto-Match panel in Reconcile.cshtml
with confidence highlights and Apply All button.

Feature 8: Late Payment Prediction — PredictLatePayments endpoint scores open AR
customers by risk (high/medium/low) using historical avg-days-to-pay + late rate;
rendered as badge table in AR Aging view via ar-aging-ai.js.

Feature 9: Natural Language Financial Queries — FinancialQuery GET page + RunFinancialQuery
POST; 12-month context snapshot pre-loaded; answers grounded in real data with
supporting facts, follow-up suggestions, session history, and example chips.

Feature 10: Recurring Bill Detection — RunRecurringDetection scans 12 months of bills
for vendor payment patterns (monthly/quarterly/annual); card grid view in Bills/RecurringDetection.cshtml
with confidence badges, next-expected-date, and suggested actions.

Supporting: 4 new DTO groups in AccountingAiDtos.cs, 4 method signatures in
IAccountingAiService.cs, 4 implementations in AccountingAiService.cs, 4 new
AiFeatures constants, 2 new Landing page AI report cards.

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

src/PowderCoating.Web/Views/Bills/Index.cshtml

@@ -5,7 +5,10 @@
     ViewData["PageIcon"] = "bi-receipt-cutoff";
 }
 
-<div class="d-flex justify-content-end mb-4">
+<div class="d-flex justify-content-between align-items-center mb-4">
+    <a asp-action="RecurringDetection" class="btn btn-outline-secondary btn-sm">
+        <i class="bi bi-robot me-1"></i>Detect Recurring Bills
+    </a>
     <div class="btn-group">
         <a asp-controller="Bills" asp-action="Create" class="btn btn-primary">
             <i class="bi bi-plus-lg me-1"></i>New Bill