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/claude/capability.json

@@ -7,7 +7,7 @@
   "tier": "core",
   "requires": [],
   "engines": {
-    "gsd": ">=1.6.0"
+    "msd": ">=1.6.0"
   },
   "runtime": {
     "configHome": {
@@ -24,7 +24,7 @@
         {
           "kind": "skills",
           "destSubpath": "skills",
-          "prefix": "gsd-",
+          "prefix": "msd-",
           "nesting": "flat",
           "recursive": false,
           "converter": "convertClaudeCommandToClaudeSkill"
@@ -32,7 +32,7 @@
         {
           "kind": "agents",
           "destSubpath": "agents",
-          "prefix": "gsd-",
+          "prefix": "msd-",
           "nesting": "flat",
           "recursive": false,
           "converter": null
@@ -42,7 +42,7 @@
         {
           "kind": "commands",
           "destSubpath": "commands",
-          "prefix": "gsd-",
+          "prefix": "msd-",
           "nesting": "flat",
           "recursive": false,
           "converter": null
@@ -50,7 +50,7 @@
         {
           "kind": "agents",
           "destSubpath": "agents",
-          "prefix": "gsd-",
+          "prefix": "msd-",
           "nesting": "flat",
           "recursive": false,
           "converter": null
@@ -105,15 +105,15 @@
         "local": "settings.local.json",
         "global": "settings.json"
       },
-      "sourceMarkerFile": ".gsd-source",
+      "sourceMarkerFile": ".msd-source",
       "agentFrontmatterExtensions": [
         "effort"
       ],
       "ownsClaudePaths": true,
       "nativeModelAliases": true,
       "skillsGlobalOnboarding": true,
-      "legacyCommandsGsdInstallMigration": true,
-      "legacyCommandsGsdUninstall": "global",
+      "legacyCommandsMsdInstallMigration": true,
+      "legacyCommandsMsdUninstall": "global",
       "hyphenNameAgentBody": true
     }
   },