feat(practice-domain): add practice domains and let a clinic select one

A practice domain is the field a clinic operates in — beauty, dentistry —
and unlike Specialty it is configuration, not a label: treatment workflows
will bind to its code, so the code is immutable once created and only a
platform admin can mint one. A clinic that has not chosen a domain keeps
behaving exactly as it does today.

Assignment reuses PATCH /api/v1/clinic/{uuid} rather than adding a second
endpoint. An unknown domain uuid is rejected instead of silently dropped,
because a lost selection would only surface at the first protocol-driven
booking.

Also corrects ADR-0003: resource occupancy does not in fact guard the panel
booking path, which writes appointments.resource_id and no occupancy row at
all, so the doctor slot key cannot simply be dropped.

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

src/Clinic/Entity/Clinic.php

@@ -36,6 +36,16 @@ class Clinic
     #[ORM\Column(type: 'string', length: 255, nullable: true)]
     private ?string $name = null;
 
+    /**
+     * حوزهٔ فعالیت کلینیک — تعیین می‌کند کدام `TreatmentWorkflow` صدا زده شود.
+     *
+     * `null` یعنی تنظیم‌نشده و رفتار پیش‌فرض، نه خطا: کلینیک‌های موجود بدون انتخاب
+     * حوزه باید دقیقاً مثل امروز کار کنند.
+     */
+    #[ORM\ManyToOne(targetEntity: \App\PracticeDomain\Entity\PracticeDomain::class)]
+    #[ORM\JoinColumn(name: 'practice_domain_id', referencedColumnName: 'id', nullable: true, onDelete: 'SET NULL')]
+    private ?\App\PracticeDomain\Entity\PracticeDomain $practiceDomain = null;
+
     #[ORM\Column(type: 'text', nullable: true)]
     private ?string $info = null;
 
@@ -153,6 +163,7 @@ class Clinic
     public function getCreatedAt(): int           { return $this->createdAt; }
     public function getUpdatedAt(): int { return $this->updatedAt; }
     public function getDoctors(): Collection    { return $this->doctors; }
+    public function getPracticeDomain(): ?\App\PracticeDomain\Entity\PracticeDomain { return $this->practiceDomain; }
 
     public function hasDoctor(Doctor $doctor): bool { return $this->doctors->contains($doctor); }
 
@@ -184,6 +195,7 @@ class Clinic
     public function setSocialMedia(?array $v): self  { $this->socialMedia = $v; $this->touch(); return $this; }
     public function setClinicLogo(?string $v): self      { $this->clinicLogo = $v; $this->touch(); return $this; }
     public function setNotificationMobile(?string $v): self { $this->notificationMobile = $v; $this->touch(); return $this; }
+    public function setPracticeDomain(?\App\PracticeDomain\Entity\PracticeDomain $v): self { $this->practiceDomain = $v; $this->touch(); return $this; }
 
     private function touch(): void { $this->updatedAt = time(); }
 
@@ -231,6 +243,7 @@ class Clinic
             ], $this->specialties->toArray()),
             'doctors'           => $this->doctors->count(),
             'doctor_list'       => null,
+            'practice_domain'   => $this->practiceDomain?->toArray(),
             'city'              => $cityData ? [$cityData] : [],
             'state'             => $provinceData ? [$provinceData] : [],
             'location'          => $address,