feat: remove obsolete date range override

migrations/Version20260831144511.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Drops the per-assignment date range override (assignment.date_from / date_to).
+ *
+ * The columns were never writable from the UI and hold no data; every consumer now reads the
+ * destination's dates directly. See .ddev/plans/remove-assignment-date-override.md.
+ */
+final class Version20260831144511 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Drop the unused per-assignment date range override columns';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE assignment DROP date_from, DROP date_to');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE assignment ADD date_from DATE DEFAULT NULL COMMENT \'(DC2Type:date_immutable)\', ADD date_to DATE DEFAULT NULL COMMENT \'(DC2Type:date_immutable)\'');
+    }
+}