feat: port tauri create-service payment flow to admin session settlement

Port the tauri /files/create-service page (payment mode) to the admin SPA
and back it with real multi-part session settlement:

Backend:
- New SessionPayment entity (session_payments table): partial payments
  per session with method (wallet/pos/cash/card), amount, paid_at, actor
- PatientSession: settlement discount (percent/fixed), discount_rials,
  paid_at, payments relation; remaining debt derived from
  final - discount - paid total
- POST /api/v1/session/{uuid}/payments: register a partial payment;
  wallet method debits the patient wallet; zero remaining marks paid
- PATCH /api/v1/session/{uuid}: accepts discount_type/discount_value
  (null removes) and paid_at, backward compatible
- New error codes: ERR_SESSION_PAYMENT_INVALID/_EXCEEDS,
  ERR_SESSION_DISCOUNT_INVALID
- Migration + 14 functional tests (partial/full/wallet/exceed/discount)

Frontend (admin):
- SessionPaymentPage: two-step stepper (پرداخت ← جزییات) ported from
  tauri AddService payment mode — service cost, settlement discount
  input, Jalali payment date, wallet balance, 4-method payment accordion,
  paid-list box, details summary
- SessionStepper + stepper/payment icons ported verbatim from tauri SVGs
- «تکمیل پرداخت» on SessionServiceCard now navigates to the payment page
  (replaces the small settle modal on PatientDetailPage)
- Routes for patients/ and my-patients/ variants; vitest coverage
- docs/api/patient.md updated

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/Patient/Entity/PatientSession.php

@@ -54,6 +54,22 @@ class PatientSession
     #[ORM\Column(name: 'payment_method', type: 'string', length: 15)]
     private string $paymentMethod = 'pending';
 
+    /** نوع تخفیف تسویه: percent | fixed | null (بدون تخفیف) */
+    #[ORM\Column(name: 'discount_type', type: 'string', length: 10, nullable: true)]
+    private ?string $discountType = null;
+
+    /** مقدار خام تخفیف (درصد یا ریال، بسته به نوع) */
+    #[ORM\Column(name: 'discount_value', type: 'integer')]
+    private int $discountValue = 0;
+
+    /** مبلغ محاسبه‌شده‌ی تخفیف به ریال (سقف: مبلغ نهایی) */
+    #[ORM\Column(name: 'discount_rials', type: 'integer')]
+    private int $discountRials = 0;
+
+    /** زمان تسویه‌ی کامل (unix)؛ تا قبل از صفر شدن بدهی null است */
+    #[ORM\Column(name: 'paid_at', type: 'integer', nullable: true)]
+    private ?int $paidAt = null;
+
     #[ORM\Column(type: 'text', nullable: true)]
     private ?string $notes = null;
 
@@ -66,6 +82,9 @@ class PatientSession
     #[ORM\OneToMany(targetEntity: SessionService::class, mappedBy: 'session', cascade: ['remove'])]
     private Collection $services;
 
+    #[ORM\OneToMany(targetEntity: SessionPayment::class, mappedBy: 'session', cascade: ['remove'])]
+    private Collection $payments;
+
     public function __construct(PatientRecord $record, ?Appointment $appointment = null)
     {
         $this->uuid        = Uuid::v4()->toRfc4122();
@@ -74,6 +93,7 @@ class PatientSession
         $this->createdAt   = time();
         $this->updatedAt   = time();
         $this->services    = new ArrayCollection();
+        $this->payments    = new ArrayCollection();
     }
 
     public function getId(): ?int             { return $this->id; }
@@ -97,6 +117,35 @@ class PatientSession
     public function getServicesTotalRials(): int { return $this->servicesTotalRials; }
     public function getFinalPriceRials(): int  { return $this->finalPriceRials; }
     public function getPaymentMethod(): string { return $this->paymentMethod; }
+    public function getDiscountType(): ?string { return $this->discountType; }
+    public function getDiscountValue(): int    { return $this->discountValue; }
+    public function getDiscountRials(): int    { return $this->discountRials; }
+    public function getPaidAt(): ?int          { return $this->paidAt; }
+    public function getPayments(): Collection  { return $this->payments; }
+
+    public function addPayment(SessionPayment $payment): self
+    {
+        if (!$this->payments->contains($payment)) {
+            $this->payments->add($payment);
+        }
+        return $this;
+    }
+
+    /** مجموع پرداخت‌های ثبت‌شده روی این مراجعه (ریال) */
+    public function getPaidTotalRials(): int
+    {
+        return array_sum(array_map(
+            fn(SessionPayment $p) => $p->getAmountRials(),
+            $this->payments->toArray(),
+        ));
+    }
+
+    /** مانده‌ی بدهی پس از کسر تخفیف و پرداخت‌ها؛ هرگز منفی نمی‌شود */
+    public function getRemainingRials(): int
+    {
+        return max(0, $this->finalPriceRials - $this->discountRials - $this->getPaidTotalRials());
+    }
+
     public function getNotes(): ?string        { return $this->notes; }
     public function getCreatedAt(): int        { return $this->createdAt; }
     public function getUpdatedAt(): int        { return $this->updatedAt; }
@@ -109,6 +158,15 @@ class PatientSession
     public function setServicesTotalRials(int $v): self                { $this->servicesTotalRials = $v; $this->updatedAt = time(); return $this; }
     public function setFinalPriceRials(int $v): self                   { $this->finalPriceRials = $v; $this->updatedAt = time(); return $this; }
     public function setPaymentMethod(string $v): self                  { $this->paymentMethod = $v; $this->updatedAt = time(); return $this; }
+    public function setDiscount(?string $type, int $value, int $rials): self
+    {
+        $this->discountType  = $type;
+        $this->discountValue = $type === null ? 0 : $value;
+        $this->discountRials = $type === null ? 0 : $rials;
+        $this->updatedAt     = time();
+        return $this;
+    }
+    public function setPaidAt(?int $v): self                           { $this->paidAt = $v; $this->updatedAt = time(); return $this; }
     public function setNotes(?string $v): self                         { $this->notes = $v; $this->updatedAt = time(); return $this; }
 
     public function toArray(): array
@@ -128,6 +186,15 @@ class PatientSession
             'final_price_rials'                  => $this->finalPriceRials,
             'payment_method'                     => $this->paymentMethod,
             'is_paid'                            => $this->paymentMethod !== 'pending',
+            'discount_type'                      => $this->discountType,
+            'discount_value'                     => $this->discountValue,
+            'discount_rials'                     => $this->discountRials,
+            'paid_at'                            => $this->paidAt,
+            'paid_total_rials'                   => $this->getPaidTotalRials(),
+            'payments'                           => array_map(
+                fn(SessionPayment $p) => $p->toArray(),
+                $this->payments->toArray()
+            ),
             'services'                           => array_map(
                 fn(SessionService $s) => $s->toArray(),
                 $this->services->toArray()

src/Patient/Entity/SessionPayment.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace App\Patient\Entity;
+
+use App\Auth\Entity\User;
+use App\Patient\Repository\SessionPaymentRepository;
+use Doctrine\ORM\Mapping as ORM;
+use Symfony\Component\Uid\Uuid;
+
+/**
+ * یک پرداختِ جزئی روی یک مراجعه (تسویه‌ی چندتکه). مجموع پرداخت‌ها به‌علاوه‌ی
+ * تخفیف، بدهیِ مراجعه را صفر می‌کند.
+ */
+#[ORM\Entity(repositoryClass: SessionPaymentRepository::class)]
+#[ORM\Table(name: 'session_payments')]
+class SessionPayment
+{
+    public const METHODS = ['wallet', 'pos', 'cash', 'card'];
+
+    #[ORM\Id]
+    #[ORM\GeneratedValue]
+    #[ORM\Column(type: 'integer')]
+    private ?int $id = null;
+
+    #[ORM\Column(type: 'string', length: 36, unique: true)]
+    private string $uuid;
+
+    #[ORM\ManyToOne(targetEntity: PatientSession::class, inversedBy: 'payments')]
+    #[ORM\JoinColumn(nullable: false, onDelete: 'CASCADE')]
+    private PatientSession $session;
+
+    #[ORM\Column(type: 'string', length: 15)]
+    private string $method;
+
+    #[ORM\Column(name: 'amount_rials', type: 'integer')]
+    private int $amountRials;
+
+    #[ORM\Column(name: 'paid_at', type: 'integer')]
+    private int $paidAt;
+
+    #[ORM\ManyToOne(targetEntity: User::class)]
+    #[ORM\JoinColumn(name: 'created_by_id', nullable: true, onDelete: 'SET NULL')]
+    private ?User $createdBy = null;
+
+    #[ORM\Column(name: 'created_by_name', type: 'string', length: 255, nullable: true)]
+    private ?string $createdByName = null;
+
+    #[ORM\Column(name: 'created_at', type: 'integer')]
+    private int $createdAt;
+
+    public function __construct(PatientSession $session, string $method, int $amountRials, ?int $paidAt = null)
+    {
+        $this->uuid        = Uuid::v4()->toRfc4122();
+        $this->session     = $session;
+        $this->method      = $method;
+        $this->amountRials = $amountRials;
+        $this->paidAt      = $paidAt ?? time();
+        $this->createdAt   = time();
+    }
+
+    public function getId(): ?int                { return $this->id; }
+    public function getUuid(): string            { return $this->uuid; }
+    public function getSession(): PatientSession { return $this->session; }
+    public function getMethod(): string          { return $this->method; }
+    public function getAmountRials(): int        { return $this->amountRials; }
+    public function getPaidAt(): int             { return $this->paidAt; }
+    public function getCreatedBy(): ?User        { return $this->createdBy; }
+    public function getCreatedByName(): ?string  { return $this->createdByName; }
+    public function getCreatedAt(): int          { return $this->createdAt; }
+
+    public function setCreatedBy(?User $u): self       { $this->createdBy = $u; return $this; }
+    public function setCreatedByName(?string $n): self { $this->createdByName = $n; return $this; }
+
+    public function toArray(): array
+    {
+        return [
+            'uuid'            => $this->uuid,
+            'method'          => $this->method,
+            'amount_rials'    => $this->amountRials,
+            'paid_at'         => $this->paidAt,
+            'created_by_name' => $this->createdByName,
+            'created_at'      => $this->createdAt,
+        ];
+    }
+}