[Feature]: Add `grep` and `glob` support in Disk

[gusye1234]

Describe the solution you'd like

Currently, Acontext can store files just like a filesystem, that means we can support agent to write/read files.

But what about searching? Current coding agents heavily rely on grep and glob, which are built-in in filesystem, but not available in Acontext

Proposed API/Interface

If applicable, describe how you envision the API or interface would look:

client.disks.grep_artifacts(disk_id='disk-uuid')
client.disks.glob_artifacts(disk_id='disk-uuid')

Component/Area

Which part of Acontext would this feature affect?

• Client SDK (Python)
• Client SDK (TypeScript)
• Core Service (Python)
• API Server (Go)
• UI/Dashboard (Next.js)
• CLI Tool
• Documentation
• Other (please specify)