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/manifest-version-sync.test.cjs

@@ -45,7 +45,7 @@ describe('A: syncManifestVersions — temp fixture', () => {
   let tmpRoot;
 
   before(() => {
-    tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-844-'));
+    tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'msd-844-'));
 
     // Write tmp package.json
     fs.writeFileSync(
@@ -107,7 +107,7 @@ describe('A: syncManifestVersions — temp fixture', () => {
   test('syncManifestVersions reports at least one changed file on first run', () => {
     // Run a fresh sync against a freshly-stale fixture to observe the changed list.
     // Create a separate sub-fixture so this test does not rely on before()'s sync order.
-    const sub = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-844-chk-'));
+    const sub = fs.mkdtempSync(path.join(os.tmpdir(), 'msd-844-chk-'));
     try {
       fs.writeFileSync(
         path.join(sub, 'package.json'),
@@ -210,7 +210,7 @@ describe('B2: native capability manifests match package.json version', () => {
 describe('B3: syncCapabilityVersions — temp fixture', () => {
 
   test('stamps stale capability manifests to package version, then is idempotent', () => {
-    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-844-cap-'));
+    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'msd-844-cap-'));
     try {
       fs.writeFileSync(
         path.join(tmpRoot, 'package.json'),
@@ -245,7 +245,7 @@ describe('B3: syncCapabilityVersions — temp fixture', () => {
   });
 
   test('listCapabilityManifests returns [] when there is no capabilities/ dir', () => {
-    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-844-nocaps-'));
+    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'msd-844-nocaps-'));
     try {
       assert.deepEqual(listCapabilityManifests({ root: tmpRoot }), []);
     } finally {
@@ -324,7 +324,7 @@ describe('C: regression guard — version-bearing JSON files must be registered'
 describe('E: stageManifests — non-git dir is a no-op, not a throw', () => {
 
   test('stageManifests({root}) with a non-git tempdir warns and returns without throwing', () => {
-    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-844-nogit-'));
+    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'msd-844-nogit-'));
     try {
       // Write a minimal package.json so getPackageVersion doesn't error if called
       fs.writeFileSync(
@@ -344,7 +344,7 @@ describe('E: stageManifests — non-git dir is a no-op, not a throw', () => {
 // ─── D: CLI --check exits 0 when in sync ─────────────────────────────────────
 // Moved to `npm run lint:generated-sync` (sync-manifest-versions.cjs --check),
 // which runs against the committed manifests in both local and CI lint lanes
-// instead of being masked by gsd-test's `npm run build` leg.
+// instead of being masked by msd-test's `npm run build` leg.
 
 // ─── F: version script includes capability-registry regen (#1498) ─────────────
 //
@@ -433,7 +433,7 @@ describe('A2: .claude-plugin/marketplace.json', () => {
     assert.ok(Array.isArray(manifest.plugins) && manifest.plugins.length > 0, 'plugins must be a non-empty array');
   });
 
-  test('plugins[0] has the gsd-core entry with source "./"', (t) => {
+  test('plugins[0] has the msd-core entry with source "./"', (t) => {
     if (!manifest) { t.skip('manifest could not be parsed'); return; }
     const entry = manifest.plugins[0];
     assert.ok(entry && typeof entry === 'object', 'plugins[0] must be an object');
@@ -537,7 +537,7 @@ describe('D: getByPath / setByPath reject reserved properties', () => {
 describe('C2: syncManifestVersions stamps plugins[0].version (temp fixture)', () => {
 
   test('stamps a stale marketplace plugins[0].version to the package version, then is idempotent', () => {
-    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-1855-'));
+    const tmpRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'msd-1855-'));
     try {
       fs.writeFileSync(
         path.join(tmpRoot, 'package.json'),