Hermes WebUI Desktop v0.3.4

Fixed

• Clicking a link in chat did nothing instead of opening the browser.
  The WebUI renders chat links with target="_blank", and our injected script
  forwarded those clicks to native by emitting an open-external IPC event.
  That emit posts to ipc.localhost, which the remote page's own CSP
  connect-src blocks (the WebUI server governs the page's CSP, not the shell),
  so the event never reached Rust and the click was a no-op. External links
  (and window.open) now navigate the top frame instead: the native
  on_navigation hook — which is not subject to the page CSP — opens external
  hosts in the system browser and cancels the navigation so the page stays put,
  exactly as plain links already did. No server-side change required.
  (#12, reported by Deor; cross-ref hermes-webui#4040.)
• White flash when opening a new tab (Windows/Linux). A new tab is a child
  webview added to an already-visible window, so it painted white until its
  first paint — the window-level anti-flash (build hidden, reveal on load)
  couldn't cover it. New tab webviews now get an opaque native background in the
  cached theme color, so they come up theme-colored instead of white. (#4,
  reported by Rod.)