Rename Go module paths to repo.anhonesthost.net/CyberCoveLLC/threshold

Rename root, api and sdk module paths (imports, go.mod, go_package,
ldflags, build scripts, buf configs) and regenerate protobuf/gateway
code with the project's pinned toolchain. Wire identifiers unchanged.
api gets a local replace for sdk; root/api/sdk require v0.1.0.

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

README.md

@@ -30,8 +30,8 @@ Boundary CE deployments working:
 - The command-line binary is now `threshold` (built from `cmd/threshold`).
 - The wire protocol, HTTP API paths (`/v1`), database schema, plugin protocol
   and configuration file format are unchanged.
-- The Go module path is still `github.com/hashicorp/boundary` for now; it will
-  change in a later phase together with regenerated protobuf code.
+- The Go module path is `repo.anhonesthost.net/CyberCoveLLC/threshold` (with `/api` and `/sdk`
+  submodules); protobuf code has been regenerated for it.
 - Release versions are still reported on the wire with the upstream
   `Boundary v` prefix so mixed clusters keep working. `Threshold v` is also
   accepted when parsing.