refactor(docs)!: rename CLI binary to corestack-docs

go install names binaries after the directory, so cmd/docs installed an
ambiguous `docs` binary into $GOBIN that could clobber or be clobbered
by other tools. Move it to cmd/corestack-docs, matching corestack-goose,
and update goreleaser, CI, docs and usage text. Accepted ADRs keep their
text and gain a dated rename note.

BREAKING CHANGE: `go install go.auvem.com/corestack/cmd/docs@latest`
stops resolving after the next tag; use cmd/corestack-docs. @v0.1.0
still installs the old `docs` binary.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/workflows/docs-check.yml

@@ -12,4 +12,4 @@ jobs:
         with:
           go-version-file: go.mod
           cache: false
-      - run: go run ./cmd/docs check
+      - run: go run ./cmd/corestack-docs check