Remove vLatest concept and associated files

Remove the concept of "vLatest" throughout the codebase to encourage use of McpbManifestAny which supports all manifest versions. Changes include:

- Delete src/schemas/latest.ts and src/schemas_loose/latest.ts
- Remove vLatest and latest-related exports from schema index files
- Remove McpbManifestLatest type, replace McpbManifest to point to McpbManifestAny
- Remove LATEST_MANIFEST_VERSION, LATEST_MANIFEST_SCHEMA constants
- Update all main export files (index.ts, cli.ts, node.ts) to export from 0.3.js instead of latest.js
- Update tests to use v0_3.McpbManifestSchema explicitly
- Add @deprecated annotation to McpbManifest directing users to McpbManifestAny

This encourages better version compatibility by using the union type that supports all manifest versions rather than assuming a single "latest" version.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/cli.ts

@@ -3,7 +3,7 @@ export * from "./cli/init.js";
 export * from "./cli/pack.js";
 
 // Include all shared exports
-export * from "./schemas/latest.js";
+export * from "./schemas/0.3.js";
 export * from "./shared/config.js";
 export * from "./shared/constants.js";
 export * from "./types.js";