Fix uv tool self-upgrade recovery

[muqiao215]

Summary

• fix uv tool self-upgrade command construction to use flags supported by older uv releases
• distinguish runtime path pollution from package-version drift so packaged installs can self-heal via reinstall
• add regression coverage for both upgrade guardrails

Validation

• pytest tests/infra/test_install.py tests/infra/test_updater.py tests/infra/test_version.py -q
• manually repaired racknerd-436b0c0 with /root/.local/bin/uv tool install --force controlmesh==0.34.10 --python python3.12
• verified racknerd-436b0c0 runtime after restart: controlmesh --version = 0.34.10, package metadata = 0.34.10, import path = uv tool site-packages

Incident context

• racknerd-436b0c0 previously failed Telegram-driven self-upgrade while on uv 0.10.10
• that host accepts uv tool install --force ... but not the old --force-reinstall path used by the app