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/hook-validation.test.cjs

@@ -1,5 +1,5 @@
 /**
- * GSD Tools Tests - Hook Field Validation
+ * MSD Tools Tests - Hook Field Validation
  *
  * Tests for validateHookFields() which prevents silent settings.json
  * rejection by removing hook entries that fail Claude Code's Zod schema.
@@ -7,7 +7,7 @@
 
 'use strict';
 
-process.env.GSD_TEST_MODE = '1';
+process.env.MSD_TEST_MODE = '1';
 
 const { test, describe } = require('node:test');
 const assert = require('node:assert/strict');
@@ -21,7 +21,7 @@ function clone(obj) {
 }
 
 /** Build a valid command hook entry. */
-function commandEntry(command, matcher = 'gsd-test') {
+function commandEntry(command, matcher = 'msd-test') {
   return {
     matcher,
     hooks: [{ type: 'command', command }],
@@ -29,7 +29,7 @@ function commandEntry(command, matcher = 'gsd-test') {
 }
 
 /** Build a valid agent hook entry. */
-function agentEntry(prompt, matcher = 'gsd-test') {
+function agentEntry(prompt, matcher = 'msd-test') {
   return {
     matcher,
     hooks: [{ type: 'agent', prompt }],