Fix (#13214): split mailrule maximum_age clamp into its own migration (#13231)

Avoids a Postgres error where the clamp UPDATE and the following ALTER TABLE on paperless_mail_mailrule share a transaction, but the table's FKs are deferrable, so pending trigger events block the ALTER. 

Also fixes a verbose_name mismatch in migration 0013.

src/paperless/migrations/0013_applicationconfiguration_llm_request_timeout.py

@@ -17,7 +17,7 @@ class Migration(migrations.Migration):
             field=models.PositiveSmallIntegerField(
                 null=True,
                 validators=[django.core.validators.MinValueValidator(1)],
-                verbose_name="Sets the LLM request timeout in seconds",
+                verbose_name="Sets the LLM timeout in seconds",
             ),
         ),
     ]

src/paperless_mail/migrations/0001_1_clamp_mailrule_maximum_age.py

@@ -0,0 +1,27 @@
+# Split out of 0002_optimize_integer_field_sizes.py into its own migration
+# (own transaction). Running this UPDATE in the same transaction as the
+# later ALTER TABLE on paperless_mail_mailrule can fail on PostgreSQL with
+# "cannot ALTER TABLE because it has pending trigger events", since the
+# update queues FK trigger events against that table that are still pending
+# when the subsequent AlterField tries to rewrite it. Committing the clamp
+# here first avoids that.
+from django.db import migrations
+
+
+def clamp_mailrule_maximum_age(apps, schema_editor):
+    # Clamp the maximum_age field of MailRule because of PositiveIntegerField --> PositiveSmallIntegerField
+    MailRule = apps.get_model("paperless_mail", "MailRule")
+    MailRule.objects.filter(maximum_age__gt=32767).update(maximum_age=32767)
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("paperless_mail", "0001_squashed"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            clamp_mailrule_maximum_age,
+            migrations.RunPython.noop,
+        ),
+    ]

src/paperless_mail/migrations/0002_optimize_integer_field_sizes.py

@@ -4,15 +4,9 @@ from django.db import migrations
 from django.db import models
 
 
-def clamp_mailrule_maximum_age(apps, schema_editor):
-    # Clamp the maximum_age field of MailRule because of PositiveIntegerField --> PositiveSmallIntegerField
-    MailRule = apps.get_model("paperless_mail", "MailRule")
-    MailRule.objects.filter(maximum_age__gt=32767).update(maximum_age=32767)
-
-
 class Migration(migrations.Migration):
     dependencies = [
-        ("paperless_mail", "0001_squashed"),
+        ("paperless_mail", "0001_1_clamp_mailrule_maximum_age"),
     ]
 
     operations = [
@@ -118,10 +112,6 @@ class Migration(migrations.Migration):
                 verbose_name="consumption scope",
             ),
         ),
-        migrations.RunPython(
-            clamp_mailrule_maximum_age,
-            migrations.RunPython.noop,
-        ),
         migrations.AlterField(
             model_name="mailrule",
             name="maximum_age",