chore: stop tracking the compiled shots binary

8.9 MB of macOS binary in the repository root, committed by accident in
a8e523b. The source in tools/shots is the thing that matters, and it is
still there.

Ignored as well as removed, because `go build ./tools/shots` without -o
writes the binary to exactly this path — which is how it got committed the
first time, and would be how it got committed the next.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.gitignore

@@ -45,3 +45,8 @@ node_modules/
 # the process is killed, which during a hung build is exactly what happens. One
 # was committed by accident.
 /web/vite.config.js.timestamp-*.mjs
+
+# A compiled `go build ./tools/shots` in the repo root. It was committed once by
+# accident — 8.9 MB of macOS binary — and `go build ./tools/shots` without -o puts
+# it right back.
+/shots