fix: remove public/llms.txt to resolve route conflict (500 error)

Both public/llms.txt and src/app/llms.txt/route.ts existed, causing
Next.js to throw 500 on /llms.txt requests. AI bots (ChatGPT, Claude,
Perplexity) were getting errors instead of reading the GEO content.

Kept the route.ts version since it has:
- More detailed Q&A and comparison sections
- Niche keywords explicitly listed
- Proper cache-control headers
- force-static for build-time generation

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dotsystemsdevs