Wrap script in main() to prevent line-by-line execution bug

When run via `bash <(curl ...)`, bash reads the script incrementally
from a process substitution fd. If a `read < /dev/tty` call disrupts
the fd state, bash can lose its place and the remaining script lines
get fed to the interactive shell prompt as individual commands.

Wrapping everything in main() forces bash to parse the entire script
into memory before executing any of it — the standard fix for
curl-piped scripts.

Also changed README one-liner to download-then-execute pattern
(curl -o /tmp/... && bash /tmp/...) as a belt-and-suspenders approach.

https://claude.ai/code/session_01XKYC1basxdwtHy71tky7xm

README.md

@@ -10,7 +10,7 @@
 ## Quick install
 
 ```bash
-bash <(curl -fsSL https://raw.githubusercontent.com/outis1one/openwhispr-easy-setup/main/setup-openwhispr.sh)
+curl -fsSL https://raw.githubusercontent.com/outis1one/openwhispr-easy-setup/main/setup-openwhispr.sh -o /tmp/setup-openwhispr.sh && bash /tmp/setup-openwhispr.sh
 ```
 
 Or clone and run: