fix: add schemas re-export file and update tests to use correct manifest version

- Create src/schemas.ts to re-export from schemas/index.ts for test imports
- Update test manifests to use manifest_version "0.2" instead of "1.0" or "1.0.0"
- Fix import sorting and formatting issues in schema files
- Export McpbManifestSchema from schemas/index.ts

src/node/validate.ts

@@ -6,7 +6,10 @@ import { join, resolve } from "path";
 import prettyBytes from "pretty-bytes";
 
 import { unpackExtension } from "../cli/unpack.js";
-import { CURRENT_MANIFEST_SCHEMA, CURRENT_MANIFEST_SCHEMA_LOOSE } from "../shared/constants.js";
+import {
+  CURRENT_MANIFEST_SCHEMA,
+  CURRENT_MANIFEST_SCHEMA_LOOSE,
+} from "../shared/constants.js";
 
 export function validateManifest(inputPath: string): boolean {
   try {