feat: complete person identity matching system with fuzzy detection, revert, and manual link

Implements the full identity matching engine: email matching (HIGH confidence),
fuzzy name matching with Levenshtein distance (MEDIUM confidence, upgradable to
HIGH with DOB tiebreaker), manual link/unlink, revert confirmed matches, and
automatic detection via PersonObserver. Includes 33 comprehensive tests, frontend
integration with confirm/dismiss/unlink UI, and match indicators in the persons list.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/Models/Person.php

@@ -121,7 +121,15 @@ final class Person extends Model
     public function pendingIdentityMatch(): HasOne
     {
         return $this->hasOne(PersonIdentityMatch::class)
-            ->where('status', IdentityMatchStatus::PENDING);
+            ->where('status', IdentityMatchStatus::PENDING)
+            ->latest();
+    }
+
+    public function confirmedIdentityMatch(): HasOne
+    {
+        return $this->hasOne(PersonIdentityMatch::class)
+            ->where('status', IdentityMatchStatus::CONFIRMED)
+            ->latest();
     }
 
     public function scopeApproved(Builder $query): Builder