v0.4.1

clipboardwire v0.4.1

Two polish items on top of v0.4.0 — same protocol, same wire,
just less surprising behavior at the edges.

- **Multi-file Ctrl+C now arrives as a single clipboard set.**
  Receiver-side debounce: file completions accumulate for 500 ms,
  then the whole batch is applied to the OS clipboard at once.
  Selecting 5 files in Nautilus/Explorer/Finder + Ctrl+C → all 5
  pastable on the other machine. (v0.4.0 only left the LAST file
  on the receiver's clipboard.)
- **Tray icon live-reloads on system theme change.** A 5-second
  background poll re-runs `dark_light::detect()`; if the value
  flips, the icon swaps to the matching mono variant in place.
  Toggle dark mode mid-session and the tray catches up without a
  relaunch.

No protocol changes. v0.4.0 clients keep working unchanged.