feat: improve profile list filtering and sidebar configuration

[shellus]

Summary

• add single-select tag filter tabs with per-tag profile counts
• keep profile item tags as passive badges instead of the primary filter control
• include profile notes in list rendering and text search
• compact profile list rows by removing the platform/proxy metadata row and placing tags before notes on one line
• add runtime SIDEBAR_WIDTH configuration while preserving the default 16rem sidebar width

Tests

• npm test
• npm run build
• npx tsc -p tsconfig.json --noEmit
• npx vite build
• pytest backend/tests/test_api.py -k runtime_config

Notes

• Full local pytest currently has unrelated failures in this environment: one CDP port exhaustion test conflicts with occupied local ports, and test_vnc_manager.py requires pytest-asyncio support.