add relevance scoring for single-field prefix searches

Improvements:
- Single-field prefix searches now sort by field length (shorter = more relevant)
- Exact matches like "Wilma" will appear before longer matches like "Wilmaaaa"
- Uses LENGTH() function which is compatible across MySQL, PostgreSQL, and SQLite

Technical details:
- Added orderByRaw("LENGTH({$field}) ASC") to scopeEncryptedPrefix
- Multi-field searches remain unsorted due to database function compatibility
- For best results with sorted relevance, use single-field prefix searches

Example:
Client::encryptedPrefix('first_names', 'Wilma')->get()
// Returns: Wilma, Wilmar, Wilmaaaa (sorted by length)

Author: ginkelsoft-development

src/Traits/HasEncryptedSearchIndex.php

@@ -349,15 +349,16 @@ public function scopeEncryptedPrefix(Builder $query, string $field, string $term
             return $query->whereIn($this->getQualifiedKeyName(), $modelIds);
         }
 
-        // Fallback to database
+        // Fallback to database with relevance sorting
+        // Sort by field length (shorter matches = more relevant)
         return $query->whereIn($this->getQualifiedKeyName(), function ($sub) use ($field, $tokens) {
             $sub->select('model_id')
                 ->from('encrypted_search_index')
                 ->where('model_type', static::class)
                 ->where('field', $field)
                 ->where('type', 'prefix')
                 ->whereIn('token', $tokens);
-        });
+        })->orderByRaw("LENGTH({$field}) ASC");
     }
 
     /**
@@ -408,6 +409,8 @@ public function scopeEncryptedPrefixMulti(Builder $query, array $fields, string
         }
 
         // Fallback to database - use OR logic for multiple fields
+        // Note: Multi-field searches don't have relevance sorting due to database compatibility
+        // Use single-field searches for relevance-sorted results
         return $query->whereIn($this->getQualifiedKeyName(), function ($sub) use ($fields, $tokens) {
             $sub->select('model_id')
                 ->from('encrypted_search_index')