Chronexus Server 0.3.0

Chronexus Server 0.3.0 — maps, tokens and token icons

A GM can now prepare a table the way it is done in Roll20: drop a map, pick a token
from a catalog and click where it goes.

New

• Maps in one step: uploading or dropping a PNG/JPEG/WebP map on the board creates
  a scene at the image size, or replaces the map of the scene being edited. Use as
  map does the same for a library image. Scenes are never shown to players until the
  GM activates them.
• Click placement: saved monsters and library images can be armed and placed on
  clicked cells until Esc; Enter places at the map centre for keyboard use. Each
  monster token keeps private HP/AC and its stat block as a GM note.
• Token icons: the public catalog adds game-icons.net (CC BY 3.0, a few CC0)
  next to Wikimedia Commons images and SRD 2014 monsters. The server looks up the
  icon index on one fixed api.github.com path and single inert SVGs on
  raw.githubusercontent.com; the browser draws the icon in a coloured round token
  and keeps author, licence and a modification note.
• GM library images report their original size; client-supplied sizes are never stored.
• API: new placeMonster board command, optional svg in catalog replies and optional
  width/height on library assets (additive).

Upgrade: no schema change (016). Back up first as usual
(chronexus-server backup FILE).

Works with Chronexus 0.9.0 and later for sharing; tables need Chronexus 0.13.0;
GM maps, tokens and catalogs in the desktop app need Chronexus 0.14.0.

Verified on Windows x64: full Rust test suite, Clippy with warnings denied,
rustfmt, contract drift check, 34 web DOM tests, the live game-icons catalog test,
a browser session and a native desktop GM session on a synthetic loopback server.
Container images are built by GitHub Actions for linux/amd64 and linux/arm64; the
Linux binaries attached here are extracted unchanged from those images. Native
macOS/Linux play, production TLS and LAN latency measurements remain open.