v0.15.2

feat(route-quality): add ISP backbone route detection

Add a new "线路质量检测" panel in the Performance tab.
The backend runs a traceroute from the server to the given target,
identifies backbone nodes by ASN (CN2/163/CU169/CUG/CMI/CMNET/CERNET)
and IP prefix, then classifies the route type and quality score.
The frontend defaults the target to the visitor's own IP so users can
immediately see what backbone carries traffic from the server to them.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>