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/schemas/index.ts

@@ -6,12 +6,6 @@ export * as v0_1 from "./0.1.js";
 export * as v0_2 from "./0.2.js";
 export * as v0_3 from "./0.3.js";
 export * as vAny from "./any.js";
-export * as vLatest from "./latest.js";
-export {
-  MANIFEST_VERSION as LATEST_MANIFEST_VERSION,
-  McpbManifestSchema as LatestMcpbManifestSchema,
-  McpbManifestSchema, // backwards compatibility - exports latest schema
-} from "./latest.js";
 
 /**
  * Map of manifest versions to their strict schemas

src/schemas/latest.ts

@@ -1 +0,0 @@
-export * from "./0.3.js";