fix(sdk): type SSE event payloads

Patch Effect OpenAPI generation so data-mode SSE responses expose their JSON payload schema instead of the raw data-line string wrapper. Regenerate legacy SDK types so V2Event and SessionDurableEvent remain the public payload unions.

Co-authored-by: opencode-agent[bot] <opencode-agent[bot]@users.noreply.github.com>

patches/effect@4.0.0-beta.83.patch

@@ -0,0 +1,32 @@
+diff --git a/dist/unstable/httpapi/OpenApi.js b/dist/unstable/httpapi/OpenApi.js
+index 8292ab7..9c4fd5e 100644
+--- a/dist/unstable/httpapi/OpenApi.js
++++ b/dist/unstable/httpapi/OpenApi.js
+@@ -335,7 +335,7 @@ export function fromApi(api) {
+               if (HttpApiSchema.isStreamSse(stream)) {
+                 pathOps.push({
+                   _tag: "schema",
+-                  ast: SchemaAST.getAST(stream.events),
++                  ast: stream.sseMode === "data" ? streamDataAst(stream.events) : SchemaAST.getAST(stream.events),
+                   path: ["paths", path, method, "responses", String(status), "content", contentType, "schema"]
+                 });
+                 pathOps.push({
+@@ -501,6 +501,18 @@ export function fromApi(api) {
+   return spec;
+ }
+ const reservedStreamFailureEvent = "effect/httpapi/stream/failure";
++function streamDataAst(events) {
++  const ast = SchemaAST.getAST(events);
++  if (!SchemaAST.isObjects(ast)) {
++    return ast;
++  }
++  const data = ast.propertySignatures.find(field => field.name === "data")?.type;
++  if (data === undefined) {
++    return ast;
++  }
++  const contentSchema = data.encoding?.at(-1)?.to.annotations?.contentSchema;
++  return SchemaAST.isAST(contentSchema) ? contentSchema : data;
++}
+ function extractSuccessResponseBodies(endpoint) {
+   return extractResponseBodies(HttpApiEndpoint.getSuccessSchemas(endpoint), HttpApiSchema.getStatusSuccess, resolveDescriptionOrIdentifier);
+ }