docs: FAQ entry on using caveman with ponytail (#599)

Most-asked question, and the answer was only ever in the skill file
(skills/ponytail/SKILL.md: "pair with Caveman for terse prose"), never
in the README. Added to both READMEs as the first FAQ entry.

Co-authored-by: Dietrich Gebert <dgebert@Dietrichs-MacBook-Pro.local>

Author: DietrichGebert

README.es.md

@@ -257,6 +257,9 @@ El benchmark de correctness lanza Python para las verificaciones de email y CSV;
 
 ## FAQ
 
+**¿Puedo usarlo junto con [caveman](https://github.com/JuliusBrussee/caveman)?**
+Sí, y deberías. Caveman achica lo que el agente dice; ponytail achica lo que construye. Mitades distintas, sin solapamiento: caveman deja el código intacto byte por byte, ponytail no se mete con la prosa. Charla concisa sobre código mínimo.
+
 **¿Necesita un archivo de configuración?**
 No. Un opcional `~/.config/ponytail/config.json` o la variable `PONYTAIL_DEFAULT_MODE` pueden fijar el nivel default, pero nada es obligatorio.
 

README.md

@@ -310,6 +310,9 @@ The correctness benchmark spawns Python for email and CSV checks; `python3` is t
 
 ## FAQ
 
+**Can I use it with [caveman](https://github.com/JuliusBrussee/caveman)?**
+Yes, and you should. Caveman shrinks what the agent says; ponytail shrinks what it builds. Different halves, no overlap: caveman leaves code byte-for-byte exact, ponytail stays out of the prose. Terse talk about minimal code.
+
 **Does it need a config file?**
 No. An optional `~/.config/ponytail/config.json` or `PONYTAIL_DEFAULT_MODE` env var can set the default level, but nothing is required.