v0.12.0 — fix: WSL dashboard connectivity, event dedup, version strings

Vite proxy config for WSL2 development (all /api and /ws traffic proxied through Vite dev server). WS URL derives from window.location when VITE_WS_BASE is empty. System Events panel deduplicates consecutive identical entries into a single (×N) row. Version strings updated to v0.12.0.