Make old project runnable on Go 1.27 with mise and READMEHEADmaster

- init go.mod (Go 1.27, progressbar/v3 v3.19.1) and fix import
- fix FMin returning max, remove deprecated RenderBlank, apply go fix range loops
- add mise.toml (go 1.27, tasks: build/run/check with go fix -diff/clean)
- add focused README and update .gitignore for build artifacts

1 files changed, 3 insertions, 1 deletions

diff --git a/.gitignore b/.gitignore
index f90281d..563d89d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 frames
-.DS_Store
\ No newline at end of file
+.DS_Store
+img.png
+goraytracer