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.

capabilities/code-review/capability.json

@@ -7,7 +7,7 @@
   "tier": "full",
   "requires": [],
   "engines": {
-    "gsd": ">=1.6.0"
+    "msd": ">=1.6.0"
   },
   "runtimeCompat": {
     "supported": [
@@ -19,8 +19,8 @@
     "code-review"
   ],
   "agents": [
-    "gsd-code-reviewer",
-    "gsd-code-fixer"
+    "msd-code-reviewer",
+    "msd-code-fixer"
   ],
   "hooks": [],
   "config": {