feat: default statistics filter to a rolling 12-month window

src/Model/StatisticsFilterDto.php

@@ -32,4 +32,27 @@ class StatisticsFilterDto extends AbstractFilterDto
 
         return $this;
     }
+
+    /**
+     * The lower bound actually applied to a query: the picked date, or a rolling
+     * 12-month window ending today when nothing is picked.
+     *
+     * The default lives here rather than in a nullable property so that
+     * AbstractFilterDto::isActive() still sees a fresh instance as "not filtered"
+     * (it compares properties with !==, which no two DateTimeImmutable share).
+     */
+    public function getEffectiveDateFrom(): \DateTimeImmutable
+    {
+        return $this->dateFrom ?? (new \DateTimeImmutable('today'))->modify('-12 months');
+    }
+
+    public function getEffectiveDateTo(): \DateTimeImmutable
+    {
+        return $this->dateTo ?? new \DateTimeImmutable('today 23:59:59');
+    }
+
+    public function isUsingDefaultRange(): bool
+    {
+        return null === $this->dateFrom && null === $this->dateTo;
+    }
 }