feat(sdk): add HttpApi clients and embedded host (#33445)

packages/httpapi-codegen/test/fixture.ts

@@ -0,0 +1,45 @@
+import { Schema } from "effect"
+import { HttpApi, HttpApiEndpoint, HttpApiGroup, HttpApiSchema } from "effect/unstable/httpapi"
+
+export class Missing extends Schema.TaggedErrorClass<Missing>()("Missing", {
+  message: Schema.String,
+}) {}
+
+export const Api = HttpApi.make("fixture")
+  .add(
+    HttpApiGroup.make("session")
+      .add(HttpApiEndpoint.get("health", "/session/health", { success: Schema.String }))
+      .add(
+        HttpApiEndpoint.get("list", "/session", {
+          query: { archived: Schema.optional(Schema.Boolean) },
+          success: Schema.Array(Schema.String),
+        }),
+      )
+      .add(
+        HttpApiEndpoint.get("get", "/session/:sessionID", {
+          params: { sessionID: Schema.String },
+          success: Schema.Struct({ data: Schema.String }),
+          error: Missing.pipe(HttpApiSchema.status(404)),
+        }),
+      )
+      .add(
+        HttpApiEndpoint.post("interrupt", "/session/:sessionID/interrupt", {
+          params: { sessionID: Schema.String },
+          success: HttpApiSchema.NoContent,
+        }),
+      ),
+  )
+  .add(
+    HttpApiGroup.make("event").add(
+      HttpApiEndpoint.get("subscribe", "/event", {
+        success: HttpApiSchema.StreamSse({ data: Schema.Struct({ type: Schema.String }) }).pipe(
+          HttpApiSchema.status(202),
+        ),
+      }),
+    ),
+  )
+  .add(
+    HttpApiGroup.make("system", { topLevel: true }).add(
+      HttpApiEndpoint.get("status", "/status", { success: Schema.String }),
+    ),
+  )