fix: remove unused useFinal property, fix remaining PHPStan errors

- Remove $useFinal property and setUseFinal() (MergeTree doesn't support FINAL)
- Remove buildTableReference $useFinal param
- Fix resolveTenantFromMetric mixed type handling
- Remove unreachable branch in Database::getTotal()
- Remove always-true count check in addBatch

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

Author: lohanidamodar

src/Usage/Adapter/ClickHouse.php

@@ -60,9 +60,6 @@ class ClickHouse extends SQL
 
     private Client $client;
 
-    /** @var bool Whether to use FINAL in SELECT queries to force merge-on-read (tests) */
-    private bool $useFinal = false;
-
     protected ?string $tenant = null;
 
     protected bool $sharedTables = false;
@@ -129,15 +126,6 @@ public function __construct(
         $this->client->setTimeout(30_000); // 30 seconds
     }
 
-    /**
-     * Enable or disable using FINAL in SELECT queries.
-     */
-    public function setUseFinal(bool $useFinal): self
-    {
-        $this->useFinal = $useFinal;
-        return $this;
-    }
-
     /**
      * Set the HTTP request timeout in milliseconds.
      *
@@ -521,7 +509,7 @@ private function getTableName(): string
      * @param bool|null $useFinal Whether to append FINAL clause
      * @return string Fully qualified table reference
      */
-    private function buildTableReference(string $tableName, ?bool $useFinal = null): string
+    private function buildTableReference(string $tableName): string
     {
         $escapedTable = $this->escapeIdentifier($this->database) . '.' . $this->escapeIdentifier($tableName);
         return $escapedTable;
@@ -1306,9 +1294,7 @@ public function addBatch(array $metrics, int $batchSize = self::INSERT_BATCH_SIZ
                 $rows[] = $encoded;
             }
 
-            if (count($rows) > 0) {
-                $this->insert($tableName, $rows);
-            }
+            $this->insert($tableName, $rows);
         }
 
         return true;
@@ -1331,7 +1317,11 @@ private function resolveTenantFromMetric(array $metricData): ?string
             return $tenant;
         }
 
-        return is_numeric($tenant) ? (string) $tenant : (string) ($tenant ?? '');
+        if (is_int($tenant) || is_float($tenant)) {
+            return (string) $tenant;
+        }
+
+        return null;
     }
 
     /**

src/Usage/Adapter/Database.php

@@ -189,7 +189,7 @@ public function getTotal(string $metric, array $queries = []): int
         if ($type === 'gauge') {
             // For gauge, return the last (most recently inserted) value
             $lastResult = end($results);
-            return $lastResult !== false ? ($lastResult->getValue(0) ?? 0) : 0;
+            return $lastResult->getValue(0) ?? 0;
         }
 
         // For events, SUM all values