Clean slate: Remove all content except LICENSE.md and .env.sample

Prepare for ecosystem-first reorganization by removing all existing
examples and configuration. This clean slate allows us to rebuild with
a clear structure where each ecosystem (curl, ts-fetch, ts-effect-ai,
ts-openrouter-sdk, ts-ai-sdk) is an independent project.

Evidence: Only LICENSE.md and .env.sample remain in repository root.

Author: subtleGradient