feat: add adaptive network readiness dashboard

[jacklv-coder]

What changed

• replace readiness rule v1 with component-based rule v2 for reachability, median TTFB, P95, jitter, and bandwidth
• add an adaptive terminal dashboard, concise status icons, bottleneck hints, and animated TTY progress
• keep JSON and Markdown compatibility while improving narrow-terminal and no-color output
• refresh English and Chinese README examples, GIFs, static previews, changelog, and version metadata for v0.8.0

Why

The previous report was accurate but log-heavy, and its score had sharp verdict-boundary cliffs. This release makes the result easier to understand at a glance while keeping the scoring transparent and machine-readable.

Validation

• bash -n bin/ipcheck test/smoke.sh
• bash test/smoke.sh
• git diff --check
• deterministic English and Chinese GIF/PNG regeneration
• manual PTY checks for spinner rendering, terminal-width detection, and Ctrl+C cleanup
• release CR: no P1/P2 (GPT-5.6 Sol fallback because Luna was unavailable)