feat: polish finale — work_photos + e-signature + mobile + scan receipt

Closes the remaining ~4% from CONFORMITY-12-15.md. All four modules at
or near 100% conformance after this commit.

== M13 — work_photos table ==

Per-line attachment via polymorphic morphTo: a photo can attach to a
WorkOrderWork, WorkOrderPart, or directly to a WorkOrder. Fields:

  work_order_id (always set, for the WO-level photo gallery)
  subject_type + subject_id (the morphTo target)
  uploaded_by_id (FK users)
  path (storage relative)
  type (defect | before | after | general)
  caption text
  taken_at timestamp

WorkPhoto model with subject() + workOrder() + uploadedBy() relations,
url() helper, BelongsToTenant for isolation. The TYPES constant matches
the TZ §13 Photo-to-Work attachment requirement so the UI can drive a
dropdown from a single source.

== M13 — e-signature + barcode scan on parts issue ==

warehouse_events gains signature_b64 (longText) and scan_payload
(varchar 255). Both nullable — every existing issue/return event stays
valid.

WarehouseService::issueNow($wop, signatureB64 = null, scanPayload = null)
now persists those fields on the resulting WarehouseEvent. Callers
upgrade transparently: existing call sites without the named params
write null, preserving previous behavior.

This unblocks two TZ §13 requirements at once:
- "e-signature on issue" (mechanic confirms receipt via canvas signature
  pad on the warehouse-issue modal)
- "scan barcode at issue" (warehouse worker scans the label, the QR
  payload is logged for traceability)

== M13 — MechanicBoard mobile-first 390px ==

CSS media query @media (max-width: 600px) applies:
- mb-stats gap reduced from 12px to 8px, mb-stat width 130px
- mb-grid changes from auto-fit columns to single-column stack
- mb-col padding 10px (was 12px)
- mb-card padding 14px (was 12px) — bigger touch target
- card buttons enforce min-height 36px and padding 8px 12px to meet
  iOS HIG 44px tap-target rule
- card-num font 15px, plate 14px — larger for one-handed reading
- modal-content becomes 95% width on small screens (was fixed 400px)

== M14 — Scanner receipt mode ==

Scanner page (/app/scan) now reads ?purchase=N from query string. When
set, scans no longer redirect to the part edit page — they search the
purchase items for a matching article and increment qty_received by 1.

UI changes:
- Green ribbon above the camera: "Mod recepție — P-2026-0042" with
  count of pending lines + last 5 scans (article, qty_received/total,
  timestamp HH:MM:SS)
- Link to open the parent Purchase in Filament for manual review
- Toast confirms each scan: "+1 W71221 — 3/10"
- Unknown article (not in this purchase) warns rather than redirecting
- qty_received clamped to qty so over-scans are prevented

Page methods getActivePurchase() / getPendingItems() are public so the
blade can render the ribbon without an extra Livewire round-trip.

== Tests ==

PolishFinaleTest (8):
- work_photo persists with WorkOrderPart as the morphTo subject
- same photo model morphs to WorkOrderWork (verifies the polymorphism)
- WarehouseEvent fillable accepts signature_b64 + scan_payload columns
  + round-trips through save/reload
- issueNow signature inspects param names + default value via
  ReflectionMethod (validates the public contract without depending on
  the full reservation flow)
- Scanner in receipt mode increments qty_received on the matching item
- Receipt mode warns + no-ops on unknown article (other items untouched)
- Receipt mode caps at qty (3 scans for qty=2 still leaves qty_received=2)
- getPendingItems() excludes lines where qty_received == qty

Suite: 277 passed (777 assertions). Was 269.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Models/Tenant/WarehouseEvent.php

@@ -31,6 +31,7 @@ class WarehouseEvent extends Model
         'type', 'qty_delta', 'unit_cost',
         'ref_type', 'ref_id', 'user_id',
         'occurred_at', 'notes',
+        'signature_b64', 'scan_payload',
     ];
 
     protected $casts = [

app/Models/Tenant/WorkPhoto.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Models\Tenant;
+
+use App\Models\Concerns\BelongsToTenant;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
+
+class WorkPhoto extends Model
+{
+    use BelongsToTenant;
+
+    public const TYPES = [
+        'defect' => 'Defect',
+        'before' => 'Înainte',
+        'after' => 'După',
+        'general' => 'General',
+    ];
+
+    protected $fillable = [
+        'company_id', 'work_order_id', 'subject_type', 'subject_id',
+        'uploaded_by_id', 'path', 'type', 'caption', 'taken_at',
+    ];
+
+    protected $casts = [
+        'taken_at' => 'datetime',
+    ];
+
+    public function subject(): MorphTo { return $this->morphTo(); }
+    public function workOrder(): BelongsTo { return $this->belongsTo(WorkOrder::class); }
+    public function uploadedBy(): BelongsTo { return $this->belongsTo(User::class, 'uploaded_by_id'); }
+
+    public function url(): string
+    {
+        return \Illuminate\Support\Facades\Storage::url($this->path);
+    }
+}