Fix bug with zod ordering and default/optional methods

[charliepark]

There were two issues I discovered when running this generator against https://github.com/oxidecomputer/console. This PR addresses them and adds a few tests.

First, a commit I made yesterday introduced an ordering bug, where zod schemas had a default() dropped in before the constraints (min, max), as in here:
-"mvlan": z.number().default(null).min(0).max(65535).nullable().optional(),
This is now fixed so that the default gets added after the constraints:
+"mvlan": z.number().min(0).max(65535).nullable().default(null),

Second, the generator shouldn't generate both default and optional on the same record.

-"multicastIp": z.ipv4().nullable().default(null).optional(),
+"multicastIp": z.ipv4().nullable().default(null),

[david-crespo]

I think you can do without skipDefault — the snapshots still pass after this change:

diff --git a/oxide-openapi-gen-ts/src/schema/zod.ts b/oxide-openapi-gen-ts/src/schema/zod.ts
index f240fc8e50..7fe7a88555 100644
--- a/oxide-openapi-gen-ts/src/schema/zod.ts
+++ b/oxide-openapi-gen-ts/src/schema/zod.ts
@@ -85,11 +85,9 @@
   },
 
   integer(schema, io) {
-    schemaToZodInt(schema, io, { skipDefault: schema.nullable });
-    if (schema.nullable) {
-      io.w0(".nullable()");
-      io.w0(getDefaultString(schema));
-    }
+    schemaToZodInt(schema, io);
+    if (schema.nullable) io.w0(".nullable()");
+    io.w0(getDefaultString(schema));
   },
 
   array(schema, io) {
@@ -201,11 +199,7 @@
   },
 });
 
-function schemaToZodInt(
-  schema: OpenAPIV3.SchemaObject,
-  { w0 }: IO,
-  options?: { skipDefault?: boolean }
-) {
+function schemaToZodInt(schema: OpenAPIV3.SchemaObject, { w0 }: IO) {
   if ("enum" in schema) {
     /**  See comment in {@link setupZod} */
     w0(`IntEnum(${JSON.stringify(schema.enum)} as const)`);
@@ -230,8 +224,4 @@
     // It's signed so remove the most significant bit
     w0(`.max(${Math.pow(2, parseInt(size) - 1) - 1})`);
   }
-
-  if (!options?.skipDefault) {
-    w0(getDefaultString(schema));
-  }
 }

[david-crespo]

This doesn't happen in our spec and the schema generator probably wouldn't let it happen, but I suppose it's fine to be defensive. Plus you can manually build a schema in the API if you really want to.