refactor: hard-fork GSD -> MSD (Make Software Done)

Mechanical rename produced by scripts/msd-rename.cjs: gsd/Gsd/GSD -> msd/Msd/MSD
across contents and paths, upstream package/repo coordinates -> @golem15/msd-core
and golem15com/msd-core. Deep links into upstream history, sibling upstream
packages, the GSD-2 import feature, CHANGELOG.md and .changeset/ are kept as-is.

Hand edits on top: MSD block-letter banner and logos, LICENSE copyright line,
package/plugin identity, regenerated lockfile, install-tree fixtures, derived
registries and benchmark baseline; migration checksum baseline re-locked
(MSD keeps its own install state, so no install had applied the old sums);
sort-order and regex-escaped expectations in tests adjusted.

scripts/check-env.cjs

@@ -23,7 +23,7 @@
 //   npm engines:         https://docs.npmjs.com/cli/v10/configuring-npm/package-json#engines
 //   Reproducible builds: https://reproducible-builds.org/docs/source-tree/
 //   npm ci docs:         https://docs.npmjs.com/cli/v10/commands/npm-ci
-//   gsd-test-runner:     https://github.com/open-gsd/gsd-test-runner
+//   msd-test-runner:     https://github.com/open-gsd/gsd-test-runner
 
 const fs = require('fs');
 const path = require('path');
@@ -37,9 +37,9 @@ const { describeNpmVersionCheckFailure } = require('./lib/npm-version-check-diag
 // is even a node_modules to build with) -- confirmed the hard way, by a
 // MODULE_NOT_FOUND crash on every real CI platform after a first attempt at
 // this fix routed the npm-version check through the canonical execNpm seam
-// (gsd-core/bin/lib/shell-command-projection.cjs), a tsc-compiled artifact
+// (msd-core/bin/lib/shell-command-projection.cjs), a tsc-compiled artifact
 // that plain does not exist yet at that point in the pipeline. This file
-// must stay self-contained: no requires reaching into gsd-core/bin/lib.
+// must stay self-contained: no requires reaching into msd-core/bin/lib.
 //
 // On Windows, npm ships as npm.cmd (a batch wrapper); spawnSync without
 // shell:true requires the exact filename including extension.