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.

tests/workflow-shell-pinning.test.cjs

@@ -1,13 +1,13 @@
 'use strict';
 
-process.env.GSD_TEST_MODE = '1';
+process.env.MSD_TEST_MODE = '1';
 
 /**
  * Asserts that every `run:` step whose command begins with `npm ` in any
  * .github/workflows/*.yml file has an effective `shell:` directive that is
  * H1-policy-compliant (native shell per OS).
  *
- * H1 policy (LOCKED — open-gsd/gsd-core):
+ * H1 policy (LOCKED — golem15com/msd-core):
  *   ubuntu-* → bash (runner default, no pin needed)
  *   macos-*  → zsh  (must be pinned explicitly)
  *   windows-* → pwsh (runner default, no pin needed)
@@ -325,7 +325,7 @@ function findViolations(filePath) {
  * Used by the defaults.run.shell unit test below.
  */
 function findViolationsInString(yamlContent) {
-  const tmpPath = path.join(require('os').tmpdir(), `gsd-shell-test-${process.pid}.yml`);
+  const tmpPath = path.join(require('os').tmpdir(), `msd-shell-test-${process.pid}.yml`);
   fs.writeFileSync(tmpPath, yamlContent, 'utf8');
   try {
     return findViolations(tmpPath);