feat(wpmc S3): procedural wpmc_* API + smoke test

Also fixes PluginBootTest to be order-independent (reset booted flag)
and to expect ShortcodeDmr hook that boot() now wires.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/HelpersTest.php

@@ -197,4 +197,17 @@ final class HelpersTest extends TestCase
         self::assertSame('mailto:x@y.com', Helpers::remove_domain_link('mailto:x@y.com'));
         self::assertSame('not a url', Helpers::remove_domain_link('not a url'));
     }
+
+    public function test_wpmc_procedural_functions_proxy_to_helpers(): void
+    {
+        require_once dirname(__DIR__) . '/includes/wpmc-functions.php';
+
+        self::assertTrue(function_exists('wpmc_current_town'));
+        self::assertTrue(function_exists('wpmc_get_term_by_slug'));
+        self::assertTrue(function_exists('wpmc_alt_get_field'));
+        self::assertTrue(function_exists('wpmc_remove_domain_link'));
+
+        // remove_domain_link is pure (no WP function dependencies) — exercise the proxy.
+        self::assertSame('/foo/', wpmc_remove_domain_link('https://site.com/foo/'));
+    }
 }