fix(billing): tolerate ReflectionTypeLoadException during init

ConfigureBillingService() walks AppDomain.CurrentDomain.GetAssemblies()
and calls Assembly.GetTypes() on each. If any of the loaded assemblies
has a type that fails to resolve (a flaky dependency, an AddOn with a
broken reference, a test dependency that's been rewritten after compile),
GetTypes() throws ReflectionTypeLoadException (or, less commonly,
FileNotFoundException / TypeLoadException for the assembly itself).

In CI on the forgejo-runner (and especially in test discovery under
xunit v3), one such assembly is loaded somewhere between test runs and
silently throws. The exception is not handled, so:

  1. Collections are Cleared at the top of ConfigureBillingService().
  2. The reflection loop throws before reaching the
     RegisterBilling<HairCutQuery/HairMultiCutQuery/RdvQuery> calls.
  3. BillingService.Billing ends up empty (Count = 0).
  4. The second ConfigureBillingService() call sees the same assembly
     loaded (xunit v3 keeps the AppDomain warm for the whole suite),
     throws identically, and the test
     Yavsc.BillingServiceTests.ConfigureBillingService_CanBeCalledTwiceWithoutThrowing
     fails with 'Assert.Equal() Failure: Expected 3, Actual 0'.

Fix: catch ReflectionTypeLoadException and use the partial
.Types() list (the successfully-resolved subset), and use a
broader catch (with continue) for any other assembly-level
load failure. The lost user-settings types are not material;
they are derived from ApplicationDbContext in a separate loop
right after, and the RegisterBilling<>() calls that populate
BillingService.Billing run last, after both reflective phases
have completed best-effort.

The test still passes locally because the local test environment
loads a clean set of assemblies; only the CI runner (with its
extra test-time tooling) hits this path.

src/Yavsc.Server/Helpers/WorkflowHelpers.cs

@@ -70,7 +70,27 @@ namespace Yavsc.Helpers
 
                 foreach (var a in System.AppDomain.CurrentDomain.GetAssemblies())
                 {
-                    foreach (var c in a.GetTypes())
+                    Type[] types;
+                    try
+                    {
+                        types = a.GetTypes();
+                    }
+                    catch (System.Reflection.ReflectionTypeLoadException rtle)
+                    {
+                        // Some referenced types failed to load; keep the
+                        // ones that did and skip the rest so a flaky
+                        // dependency in one assembly does not break
+                        // billing initialization for every other assembly.
+                        types = rtle.Types.Where(t => t != null).ToArray();
+                    }
+                    catch
+                    {
+                        // Assembly itself cannot be loaded (FileNotFoundException
+                        // on a referenced assembly, etc.). Skip it entirely.
+                        continue;
+                    }
+
+                    foreach (var c in types)
                     {
                         if (c.IsClass && !c.IsAbstract &&
                             c.GetInterface(nameof(IUserSettings)) != null)