feat: OpenCode platform support, vitest tests, changelog & Docker hardening

fix: copy scripts/ before npm ci for postinstall to find setup-curl.ts

fix: Docker build installs curl, keeps tsx, optimizes layers

fix: Dockerfile copies source before npm ci for postinstall

fix: Docker build uses host network for proxy access

fix: use BUILD_PROXY arg to avoid BuildKit proxy conflict

fix: Docker build supports proxy via .env configuration

feat: migrate dashboard to Preact + Vite

refactor: fingerprint alignment, auto-maintenance, Docker deployment