List remote documents in Knowhere MCP

[suguanYang]

Summary

• route knowhere_list_documents to the remote documents API with optional namespace filtering
• document remote document IDs as usable with outline/read/grep tools
• keep read-tool descriptions focused on identifiers and resultDirectoryPath/chunks.json, without cache mechanics

Tests

• pnpm --filter @ontos-ai/knowhere-mcp test:ci
• pnpm --filter @ontos-ai/knowhere-mcp typecheck
• git diff --cached --check
• git diff --check