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>

README.md

@@ -1,26 +1,26 @@
 # corestack go
 
-Shared Go building blocks. Includes `docs`, a checker for architecture decision records (ADRs) and implementation plans; `page`, Bob keyset pagination; and `lifecycle`, a service and worker coordinator.
+Shared Go building blocks. Includes `corestack-docs`, a checker for architecture decision records (ADRs) and implementation plans; `page`, Bob keyset pagination; and `lifecycle`, a service and worker coordinator.
 
 ## migrate
 
 [`migrate`](migrate/README.md) configures Goose providers for embedded SQL and Go
 migrations, with structured logging and Postgres startup locking.
 
-## docs
+## corestack-docs
 
 Install:
 
 ```sh
-go install go.auvem.com/corestack/cmd/docs@latest
+go install go.auvem.com/corestack/cmd/corestack-docs@latest
 ```
 
 Use, from a repository root:
 
 ```sh
-docs new adr "Use Example Queue for background jobs"   # creates docs/adr/<id>.md
-docs new plan "Adopt Example Queue"                    # creates docs/plans/<id>.md
-docs check [--root DIR]                                # prints path:line: message; exit 1 on problems
+corestack-docs new adr "Use Example Queue for background jobs"   # creates docs/adr/<id>.md
+corestack-docs new plan "Adopt Example Queue"                    # creates docs/plans/<id>.md
+corestack-docs check [--root DIR]                                # prints path:line: message; exit 1 on problems
 ```
 
 The format is specified in [docs/docs-format.md](docs/docs-format.md); that document is the complete rule set. Exit status is `0` when every record is valid, `1` when problems are reported and `2` for usage errors.