Update help docs and AI knowledge base for 4 new AI bookkeeping features

- Reports.cshtml: added AI Payment Risk Prediction, Ask Your Financials,
  and Bank Rec Auto-Match subsections under AI-Powered Reports; updated
  on-this-page nav with sub-links for all three
- AccountsPayable.cshtml: added Recurring Bill Detection section explaining
  pattern cards, frequency types, confidence badges, next expected date,
  and the 2-occurrence minimum
- HelpKnowledgeBase.cs: added Recurring Bill Detection to BILLS section;
  added AI Payment Risk Prediction and Ask Your Financials to REPORTS
  available-reports list; added features 12–15 to AI FEATURES section
  (Recurring Detection, Payment Risk, Financial Query, Bank Rec Auto-Match)

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

src/PowderCoating.Web/Views/Help/AccountsPayable.cshtml

@@ -229,6 +229,43 @@
             </p>
         </section>
 
+        <section id="recurring-detection" class="mb-5">
+            <h2 class="h4 fw-bold border-bottom pb-2 mb-3">
+                <i class="bi bi-arrow-repeat text-primary me-2"></i>Recurring Bill Detection
+            </h2>
+            <p>
+                The <strong>Detect Recurring Bills</strong> tool is accessible from the Bills list via the
+                button in the top-left of the page, or directly at
+                <a asp-controller="Bills" asp-action="RecurringDetection">/Bills/RecurringDetection</a>.
+                Click <strong>"Detect Recurring Bills"</strong> and Claude analyzes the last 12 months of your
+                bill history to find vendors you pay on a regular schedule.
+            </p>
+            <p>
+                Each detected pattern is shown as a card with:
+            </p>
+            <ul class="mb-3">
+                <li class="mb-1"><strong>Vendor name</strong> and detected frequency (monthly, quarterly, biannual, annual).</li>
+                <li class="mb-1"><strong>Typical amount</strong> — the usual charge from that vendor.</li>
+                <li class="mb-1"><strong>Next expected date</strong> — Claude's estimate of when the next bill is likely to arrive.</li>
+                <li class="mb-1"><strong>Confidence badge</strong> — High (4+ consistent occurrences), Medium (2–3 occurrences or variable timing), Low (weak pattern, worth monitoring).</li>
+                <li class="mb-1"><strong>Suggested action</strong> — for example, "Set a monthly reminder for this bill."</li>
+            </ul>
+            <p>
+                This is useful for cash flow planning — knowing that a $1,200 electricity bill arrives on the
+                15th every month, or that your insurance renews every January, lets you reserve funds in advance
+                and avoid surprises. High-confidence patterns are reliable enough to act on; Low-confidence
+                patterns are worth keeping an eye on but should not be treated as certain.
+            </p>
+            <div class="alert alert-permanent alert-info d-flex gap-2 mb-0" role="alert">
+                <i class="bi bi-lightbulb-fill flex-shrink-0 mt-1"></i>
+                <div>
+                    Recurring bill detection requires at least 2 occurrences of a vendor bill at a similar
+                    interval to detect a pattern. Shops with less than 2 months of history will see few or no
+                    results. The scan covers bills only — direct expenses are not included.
+                </div>
+            </div>
+        </section>
+
         <section id="expense-accounts" class="mb-5">
             <h2 class="h4 fw-bold border-bottom pb-2 mb-3">
                 <i class="bi bi-folder2-open text-primary me-2"></i>Expense Accounts