Latch v4.0.2

• panel.log and service.log no longer grow without end. Both were
  opened in append mode and nothing ever pruned them, so a machine that
  streams for weeks kept every line it had ever logged: Hermes reached a
  32 MB panel.log. Each file now rolls over at 4 MB, keeping one previous
  generation as <name>.1, so a log costs at most 8 MB however long the
  service or the window runs.
• The window no longer logs a line for every frame it draws. wgpu's Vulkan
  backend warns whenever a presented frame's swapchain reports suboptimal,
  which on a Windows PC is every frame; it was every single line of that
  32 MB file. The condition is normal and wgpu recreates the swapchain
  itself, so that one target is now heard from only when it is an error.
  RUST_LOG still overrides everything.