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/multi-runtime-select.test.cjs

@@ -10,7 +10,7 @@
  * instead of regexing bin/install.js source text.
  *
  * #1928: Google sunset Gemini CLI (2026-06-18) and the `gemini` runtime was
- * removed from GSD (Antigravity CLI is the successor). The runtime option
+ * removed from MSD (Antigravity CLI is the successor). The runtime option
  * numbering below is renumbered accordingly — option 9 (formerly gemini) is
  * now hermes, and the "All" shortcut moved from 17 to 16.
  *
@@ -21,7 +21,7 @@
  * shortcut moves from 17 to 18.
  */
 
-process.env.GSD_TEST_MODE = '1';
+process.env.MSD_TEST_MODE = '1';
 
 const { test, describe } = require('node:test');
 const assert = require('node:assert/strict');