feat(policy): six-category policy engine wired into the booking flow

Rules become data instead of code: a clinic can say "laser under 18 requires
parental consent" without a deploy.

Engine
- Policy / PolicyVersionLog entities, closed field/operator/effect lists per
  category (PolicySchema), condition validation at write time
- PolicyResolver: priority -> specificity -> age, combining effects by
  veto / max / sum / union
- A missing fact fails its clause instead of silently passing it
- Policies are drafts until activated, and are versioned rather than edited

Wiring
- selection -> ServiceSelectionValidator
- eligibility + spacing -> BookingPolicyGuard, at hold time not confirm time
- resource + timing -> AppointmentPlanBuilder, including template-less services
- pricing -> PricingEngine, alongside (not replacing) the manual discount

The condition column is named condition_json: `condition` is a MariaDB keyword
and broke every INSERT.

Tests: 17 in tests/Policy including NoPolicyRegressionTest, which pins that a
clinic with no policies sees byte-identical output to task 08.
Docs: docs/api/policy.md (real captured JSON) + docs/architecture/policy-engine.md.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/Pricing/Service/PricingEngine.php

@@ -9,6 +9,9 @@ use App\Doctor\Entity\DoctorAddress;
 use App\Pricing\Repository\PriceListItemRepository;
 use App\Pricing\Repository\PriceListRepository;
 use App\Pricing\ValueObject\PriceQuote;
+use App\Policy\Entity\Policy;
+use App\Policy\Service\PolicyResolver;
+use App\Policy\Service\PolicySchema;
 use App\Representation\Service\JalaliDateService;
 
 /**
@@ -33,6 +36,7 @@ use App\Representation\Service\JalaliDateService;
 final class PricingEngine
 {
     public function __construct(
+        private readonly PolicyResolver                  $policies,
         private readonly PriceListRepository             $priceLists,
         private readonly PriceListItemRepository         $priceListItems,
         private readonly ServiceBranchOverrideRepository $overrides,
@@ -73,6 +77,10 @@ final class PricingEngine
         $subtotal = $base + $itemsTotal;
 
         // ── تخفیف ─────────────────────────────────────────────────────────────
+        // قوانین دستهٔ «قیمت» کنار سیاست دستیِ درخواست می‌نشینند، نه به‌جایش: تخفیفی
+        // که اپراتور دستی می‌دهد و تخفیفی که قانون می‌دهد هر دو واقعی‌اند.
+        $policy = $this->mergePolicyDiscounts($service, $items, $address, $at, $subtotal, $policy, $sources);
+
         [$discount, $discounts] = $this->discountFor($subtotal, $policy);
 
         // تخفیف بیشتر از مبلغ، مبلغ را **صفر** می‌کند نه منفی: بدهی منفی یعنی کلینیک
@@ -116,6 +124,58 @@ final class PricingEngine
         );
     }
 
+    /**
+     * اثر قوانین «قیمت» را به سیاست درخواست اضافه می‌کند.
+     *
+     * شناسه و **نسخهٔ** هر قانون در `sources` ثبت می‌شود تا فاکتور بتواند سه ماه بعد
+     * بگوید کدام نسخه رویش اعمال شده بود.
+     *
+     * @param ServiceItem[]        $items
+     * @param array<string, mixed> $policy
+     * @param array<string, mixed> $sources
+     * @return array<string, mixed>
+     */
+    private function mergePolicyDiscounts(
+        ServiceItem $service,
+        array $items,
+        DoctorAddress $address,
+        int $at,
+        int $subtotal,
+        array $policy,
+        array &$sources,
+    ): array {
+        $outcome = $this->policies->resolve(
+            Policy::CATEGORY_PRICING,
+            $address->tenantEntityType(),
+            $address->tenantEntityId(),
+            [
+                'item_count'     => count($items),
+                'subtotal_rials' => $subtotal,
+                'patient_tags'   => $policy['patient_tags'] ?? [],
+                'visit_count'    => $policy['visit_count'] ?? 0,
+            ],
+            $address,
+            $service,
+            $at,
+        );
+
+        if ($outcome->appliedPolicies === []) {
+            return $policy;
+        }
+
+        $sources['applied_policies'] = $outcome->appliedPolicies;
+
+        $policy['discount_percent'] = (float) ($policy['discount_percent'] ?? 0)
+            + (float) $outcome->effect(PolicySchema::EFFECT_DISCOUNT_PERCENT, 0);
+
+        $policy['discount_rials'] = (int) ($policy['discount_rials'] ?? 0)
+            + (int) $outcome->effect(PolicySchema::EFFECT_DISCOUNT_RIALS, 0);
+
+        $policy['discount_label'] ??= $outcome->appliedPolicies[0]['name'];
+
+        return $policy;
+    }
+
     /**
      * @param array<string, string> $sources
      */