fix: empty filter query and cloud sync deletion bugs (#279, #251)

[zc277584121]

Summary

• Fix empty string filter in vectorDb.query() causing empty results on both gRPC and REST clients by omitting the filter field instead of sending ""
• Store codebasePath in collection description (codebasePath:<path> format) for reliable extraction during sync, with fallback to query-based extraction for backward compatibility with old collections
• Add safety guards in syncIndexedCodebasesFromCloud(): skip deletion when collections list is empty or all extractions fail, preventing accidental deletion of all local indexed codebases
• Add getCollectionDescription() to VectorDatabase interface with implementations for both MilvusVectorDatabase and MilvusRestfulVectorDatabase
• Fix REST API createCollection/createHybridCollection to pass description parameter (was previously ignored)
• Bump version to 0.1.4

Changes

File	Change
packages/core/src/vectordb/types.ts	Add getCollectionDescription to interface
packages/core/src/vectordb/milvus-vectordb.ts	Fix empty filter, implement getCollectionDescription
packages/core/src/vectordb/milvus-restful-vectordb.ts	Fix empty filter, pass description in create, implement getCollectionDescription
packages/core/src/context.ts	Change collection description format to codebasePath:<path>
packages/mcp/src/handlers.ts	Refactor sync: description-first extraction with query fallback and safety guards
*/package.json	Version bump 0.1.3 → 0.1.4

Test plan

• E2E tested with real Milvus (localhost:19530) via Claude Code CLI + MCP server
• Bug Cloud sync removes all local codebases on connection failure #251 reproduced on old code: drop all collections → sync deletes local records
• Bug Cloud sync removes all local codebases on connection failure #251 verified fixed on new code: drop all collections → local records preserved
• Backward compatibility verified: old collections without codebasePath: prefix handled via fallback
• pnpm build:core and pnpm build:mcp both succeed