feat(core): add ZILLIZ_PROJECT_NAME environment variable for configurable project name

[RauchenwaldC]

Summary

This PR adds support for configuring the Zilliz Cloud project name via the ZILLIZ_PROJECT_NAME environment variable, addressing the issue where "Default Project" was previously hardcoded.

Problem

Previously, when auto-resolving cluster addresses from a Zilliz Cloud token, the system was hardcoded to look for a project named "Default Project". This limitation prevented users from using different project names in their Zilliz Cloud accounts.

Solution

• Added support for the ZILLIZ_PROJECT_NAME environment variable
• Modified ClusterManager.getAddressFromToken() to accept an optional project name parameter
• The system now uses the following priority:
  1. Explicit project name parameter (if provided)
  2. ZILLIZ_PROJECT_NAME environment variable
  3. Falls back to "Default Project" for backward compatibility
• Improved error messages to show available projects when the specified project is not found

Changes

• packages/core/src/vectordb/zilliz-utils.ts: Updated getAddressFromToken method to support configurable project names
• packages/mcp/src/config.ts: Added zillizProjectName to configuration interface
• .env.example: Added example configuration for ZILLIZ_PROJECT_NAME
• docs/getting-started/environment-variables.md: Documented the new environment variable
• packages/mcp/README.md: Added configuration example for the new variable

Testing

• Successfully built all packages with pnpm build
• Maintains backward compatibility - existing configurations will continue to work without any changes
• When ZILLIZ_PROJECT_NAME is not set, the system defaults to "Default Project" as before

Breaking Changes

None - this change is fully backward compatible.

Related Issues

This addresses the limitation where users couldn't specify custom project names when using Zilliz Cloud's auto-resolution feature.