v0.8.2 — Hotfixes

Quick fixes for v0.8.1:

• Fix: prompt caching disabled by default (400 error on non-Anthropic providers)
• Fix: missing routing_mode field in BasicRouter
• Fix: compile errors in RoutingResponse + BasicRouter
• Feat: routing manual mode (sparrow route manual/auto)
• Feat: preferred_model pinning (sparrow route set provider/model)
• Feat: WebView routing panel with model selector + manual toggle
• Feat: compact WebView cards + user sender labels
• Feat: 'no actions taken' detection for empty runs