refactor!: retire wails.json, config.yml is the version source

- version.go (generated, never hand-edited) carries the compiled-in
  version; app.go drops the wails.json embed plus the gjson dependency
- make release bumps config.yml and regenerates version.go in one
  commit; the re-run-safe guards from the 1.99.1 cycle carry over
- release guard reads config.yml; CI CLI pin and cache key move to
  beta.22 to match the lockstep above
- release wrapper and config NOTE comments updated; deletion proof:
  wails3 build green plus a dev boot reaching the connected state
  with the file absent (the one cold-boot failure reproduced as a
  Vite 8 cold-start vs app retry race, cleared by rerunning warm)

release

@@ -4,7 +4,7 @@
 # instead of:
 #   make release VERSION=1.6.7
 # Lives in the repo (no machine-specific alias needed). Tags are plain
-# versions (1.6.7) to match wails.json productVersion.
+# versions (1.6.7) to match build/config.yml info.version.
 set -eu
 
 [ "$#" -ge 1 ] || { echo "Usage: ./release 1.6.7" >&2; exit 1; }