VERSION in makefile is now the single source of truth — it flows into
the about screen via -DAPP_VERSION at compile time and into the archive
filename via the dist target. `make dist` produces
SoundThing-<platform>-v<version>.tar.gz (Linux) or .zip (Windows)
containing the binary and the full patch library.
Also fixes a trailing-spaces-in-PROJECT makefile gotcha that was
silently embedding spaces in the binary path.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>