docs: clarify obfuscated snippet is excerpt and keep real CLI preview

Co-authored-by: levno-710 <62939318+levno-710@users.noreply.github.com>
Agent-Logs-Url: https://github.com/prometheus-lua/Prometheus/sessions/7fcb95be-0dac-4091-92e7-ef245ac81e32

Author: Copilot

readme.md

@@ -23,9 +23,11 @@ local answer = 42
 print(secret .. " -> " .. answer)
 ```
 
-```lua
+```text
 -- generated with: lua ./cli.lua --preset Medium ./simple.lua
-return(function(...)local L={"afT6mf1V","/7mJXsuvmE1c/fT3";"tn1ZSn6=","37ghSJM=";"WqermfWAWuuZpb3XX7M=","tqXGSJ3u","XQXpL9x21dxAWJa//p==","SrM=";"3q+5SJM=","/D==";"t7XUt0p=";"mIeOmIx9";"LdgrBfWdWuNABsb+KJxj","SJWJ4dahKsebW7t+KQv=","/cDu3AvP/D==";"Llv7uD==","tJWhFfTE";"TQ43ctIuy9HIop==","mEu93p==";"WJax1sXEXEaxWuxGt6==","t0gPSEp=",...}
+-- excerpt from ./simple.obfuscated.lua
+return(function(...)local L={"afT6mf1V","/7mJXsuvmE1c/fT3";"tn1ZSn6=","37ghSJM=";"WqermfWAWuuZpb3XX7M=","tqXGSJ3u","XQXpL9x21dxAWJa//p==","SrM=";"3q+5SJM=","/D==";"t7XUt0p=";"mIeOmIx9";"LdgrBfWdWuNABsb+KJxj","SJWJ4dahKsebW7t+KQv=","/cDu3AvP/D==";"Llv7uD==","tJWhFfTE";"TQ43ctIuy9HIop==","mEu93p==";"WJax1sXEXEaxWuxGt6==","t0gPSEp=",...
+... (remaining obfuscated output omitted)
 ```
 
 ## Installation