Changes:
- feat: image/PDF/text attachments for Claude Code sessions, with file preview as resizable right-side panel on desktop and SVG preview support
- feat(pwa): cross-device unread tracking with purple status; per-browser toggle to fold tool calls into expandable groups; TodoWrite "+N more" expansion and Bash command collapse; unified Bash chevron, Write content peek, sandbox-MCP cards; restore archived sessions from machine info page
- feat(agent): systemd user-unit auto-start with PWA toggle and boot helper; wire reasoningEffort to Claude --effort + SDK Options.effort
- feat(relay): active-key + traffic metrics for DAU-style tracking; expose Prometheus metrics on separate admin port
- feat(site): og-image and social metadata; bilingual .en.md / .zh-TW.md layout
- fix(agent): rebind attachments by exact UUID across JSONL replay
- fix(pwa): replay snapshot when re-subscribing with stale unsub; force-expand folded tool calls when permission pending; skip Enter-to-submit on mobile new-session input; plain 100dvh and focus-aware bottom pad for input area
- fix(site): horizontal scroll for install snippets on mobile; force Pages enablement on every deploy
- refactor(pwa): simplify chat input; positive-on-right buttons + neutral Deny; drop verbose labels on tool call group placeholder
- chore: rename to "King Young Technology" + add SPDX headers; clarify sandbox mode is an MCP tool; gitignore Vite PWA dev-dist; tidy plans folder and sync docs
- test(agent): clear XDG_CONFIG_HOME in systemdUnit tests so the homedir mock wins on CI runners