feat: person tags system - org-level skills with self-reported and organiser-assigned sources

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

api/app/Models/User.php

@@ -63,4 +63,14 @@ final class User extends Authenticatable
     {
         return $this->hasMany(UserInvitation::class, 'invited_by_user_id');
     }
+
+    public function organisationTags(): HasMany
+    {
+        return $this->hasMany(UserOrganisationTag::class);
+    }
+
+    public function tagsForOrganisation(string $organisationId): HasMany
+    {
+        return $this->organisationTags()->where('organisation_id', $organisationId);
+    }
 }