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/helpers/emitted-diff.cjs

@@ -150,11 +150,11 @@ const REMEDIATION = Object.freeze({
   addTrailerGrowth:
     'Add a trailer to a commit in this PR (never a new file). Use the '
     + `\`${ACK_TRAILER_GROWTH}\` trailer for growth (key = the bare filename as it `
-    + 'appears under gsd-core/workflows/ or agents/).',
+    + 'appears under msd-core/workflows/ or agents/).',
   doNotRegenerate:
     'Do NOT regenerate anything to silence this — there is nothing left to regenerate.',
   /** The size ratchet keys on `entry.name` from readdirSync (emitted-runtime.cjs `currentSizes`). */
-  growthKeyRule: 'Key on the BARE FILENAME as it appears under gsd-core/workflows/ or agents/',
+  growthKeyRule: 'Key on the BARE FILENAME as it appears under msd-core/workflows/ or agents/',
   /** The hash pass keys on the emitted manifest path, which always carries a `/`. */
   rippleKeyRule: 'Key on the EMITTED PATH exactly as printed above',
   rippleReason: '<why this ripple is deliberate>',
@@ -171,7 +171,7 @@ const REMEDIATION = Object.freeze({
    * negative-space note.
    */
   ackTrailerExample: renderAckTrailer(
-    ACK_TRAILER_HASH, 'skills/gsd-add-tests/SKILL.md', 'converter rewrite, ADR-2719',
+    ACK_TRAILER_HASH, 'skills/msd-add-tests/SKILL.md', 'converter rewrite, ADR-2719',
   ),
 });