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/lib/shellcheck-fetch.cjs

@@ -89,7 +89,7 @@ function httpsGetFollowingRedirects(url, redirectsLeft = MAX_REDIRECTS, requestF
   return new Promise((resolve, reject) => {
     const req = requestFn(
       url,
-      { headers: { 'User-Agent': 'gsd-core-shellcheck-fetch' }, timeout: DOWNLOAD_TIMEOUT_MS },
+      { headers: { 'User-Agent': 'msd-core-shellcheck-fetch' }, timeout: DOWNLOAD_TIMEOUT_MS },
       (res) => {
         const status = res.statusCode || 0;
         if (status >= 300 && status < 400 && res.headers.location) {