Move process wiring, technical adapters, and cross-cutting contracts out of flat internal/ packages so new code has a clear home without changing business layout.
- Updated `new-api` skill `SKILL.md` to document the centralized v1.go route registration and domain-driven sub-routing patterns
- Updated `AGENTS.md` instructions with the new router subpackages (`root`, `v1`) and route file layout guidelines
- Created `internal/router/root` package to register root-level paths
- Moved files serving, robots.txt, and Swagger docs to `root/default.go`
- Registered custom root routes under `root/custom.go`
- Centralized all v1 routes registration in `internal/router/v1/v1.go`
- Simplified `internal/router/router.go` by delegating route registration
- Updated `new-api` skill `SKILL.md` to document the new router structure
ryan