Removing an empty file frees nothing, yet every `.gitkeep`,
`__init__.py` and empty log formed one `report` group, and directories
holding only empty files were reported as 0-byte duplicate trees. Now
`report` writes no group of size 0 and `trees` writes no group whose
trees hold 0 bytes. An empty file still counts toward the digest of a
tree that holds other files. No option, as approved on the issue. The
README's definition-of-done test now expects `empty1` and `empty2`
nowhere.
Model: opus-5-5
`go install sneak.berlin/go/sfdupes/cmd/sfdupes@...` found no package: the command was built from `package main` in the repository root. It now lives in `cmd/sfdupes/main.go`, whose one call is `sfdupes.Main()`, and every other Go file moved with `git mv` to `internal/sfdupes`, as `REPO_POLICIES.md` and the Go style guide require. The `Makefile` builds `./cmd/sfdupes` and sets `Version` by its new import path. README "Install" and `TODO.md` give the new paths; the fleet-written "flat layout" divergence is gone.
Rule suppressed: each test file carries `//nolint:testpackage`, since the tests call unexported functions throughout.
Model: opus-5-5