Prove carry-forward of package migrations over customized published set

Addresses zorporation/durable-workflow#400. Follows the TD-034 close
(#32) which delivered fresh-install, publish-first, and repair-path
tests but swapped prose for an automated test on the customized-
migration path. The customized path that is actually testable in-
package is the documented "publish, keep schema-compatible edits, and
carry each new package migration forward in timestamp order" pattern —
this test exercises it end to end.

The test:

1. Publishes the package migrations, then deletes the repair migration
   (2026_04_16_000158) to simulate a snapshot taken before #32 fix.
2. Strips the memo column from the published workflow_run_summaries
   migration, simulating that older snapshot predated the memo column.
3. Adds a schema-compatible extra index on workflow_instances
   (workflow_class) to the published create_workflow_instances
   migration — a realistic user customization.
4. Drops all tables, migrates from the published path, asserts the
   schema came up without memo and with the custom index.
5. Copies the new repair migration from src/migrations/ into the
   published dir (the documented carry-forward step) and runs migrate
   again.
6. Asserts memo is now present AND the custom index survived the
   carry-forward run.

Verified in isolation (phpunit --filter
testCarryingForwardPackageMigrationOverCustomizedPublishedSet):
1 test, 9 assertions pass on PHP 8.4 + SQLite.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: durable-workflow-ops

tests/Unit/Providers/WorkflowServiceProviderTest.php

@@ -147,6 +147,99 @@ public function testPublishedMigrationsCanRunAsInstallSource(): void
         }
     }
 
+    public function testCarryingForwardPackageMigrationOverCustomizedPublishedSet(): void
+    {
+        $this->deletePublishedWorkflowMigrations();
+
+        try {
+            // 1. Publish the current package migrations.
+            Artisan::call('vendor:publish', [
+                '--tag' => 'migrations',
+                '--force' => true,
+            ]);
+
+            $publishedDir = database_path('migrations');
+            $repair = $publishedDir . '/2026_04_16_000158_repair_memo_on_workflow_run_summaries_table.php';
+            $summaries = $publishedDir . '/2026_04_05_000106_create_workflow_run_summaries_table.php';
+            $instances = $publishedDir . '/2026_04_05_000100_create_workflow_instances_table.php';
+
+            $this->assertFileExists($repair, 'Expected publish to include the repair migration.');
+            $this->assertFileExists($summaries);
+            $this->assertFileExists($instances);
+
+            // 2. Simulate a published snapshot taken before the repair
+            //    migration shipped by removing it from the published set.
+            @unlink($repair);
+
+            // 3. Simulate that older snapshot's create_workflow_run_summaries
+            //    migration predating the memo column by stripping the column
+            //    declaration from the published copy only.
+            $summariesContents = file_get_contents($summaries);
+            $memoLine = "            \$table->json('memo')\n                ->nullable();\n";
+            if (! str_contains($summariesContents, $memoLine)) {
+                $this->markTestSkipped(
+                    'workflow_run_summaries published migration no longer matches the expected layout; adjust the test.'
+                );
+            }
+            file_put_contents($summaries, str_replace($memoLine, '', $summariesContents));
+
+            // 4. Apply a schema-compatible user customization: an extra
+            //    secondary index on workflow_instances(workflow_class) that
+            //    the package does not ship.
+            $instancesContents = file_get_contents($instances);
+            $customIndex = "            \$table->index('workflow_class', 'workflow_instances_workflow_class_index');\n";
+            $hook = "            \$table->string('workflow_class');\n";
+            $this->assertStringContainsString($hook, $instancesContents);
+            file_put_contents(
+                $instances,
+                str_replace($hook, $hook . $customIndex, $instancesContents),
+            );
+
+            // 5. Run migrate from the customized published snapshot.
+            Schema::dropAllTables();
+            $this->artisan('migrate:install')
+                ->run();
+            $this->artisan('migrate', [
+                '--path' => $publishedDir,
+                '--realpath' => true,
+            ])->run();
+
+            $this->assertTrue(Schema::hasTable('workflow_run_summaries'));
+            $this->assertFalse(
+                Schema::hasColumn('workflow_run_summaries', 'memo'),
+                'Simulated older published snapshot should not yet carry the memo column.'
+            );
+            $this->assertTrue(
+                Schema::hasIndex('workflow_instances', ['workflow_class']),
+                'Custom index on the customized published migration should be present after migrate.'
+            );
+
+            // 6. Carry the newer package migration forward into the published
+            //    dir in timestamp order, per the migration-guide instructions.
+            $packageRepair = dirname(__DIR__, 3)
+                . '/src/migrations/2026_04_16_000158_repair_memo_on_workflow_run_summaries_table.php';
+            copy($packageRepair, $repair);
+
+            // 7. Re-run migrate. The repair migration should add the missing
+            //    column without disturbing the earlier customization.
+            $this->artisan('migrate', [
+                '--path' => $publishedDir,
+                '--realpath' => true,
+            ])->run();
+
+            $this->assertTrue(
+                Schema::hasColumn('workflow_run_summaries', 'memo'),
+                'Carry-forward of the repair migration should add memo to workflow_run_summaries.'
+            );
+            $this->assertTrue(
+                Schema::hasIndex('workflow_instances', ['workflow_class']),
+                'User-added custom index should survive the carry-forward migrate run.'
+            );
+        } finally {
+            $this->deletePublishedWorkflowMigrations();
+        }
+    }
+
     public function testCommandsAreRegistered(): void
     {
         $registeredCommands = array_keys(Artisan::all());