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/cursor-conversion.test.cjs

@@ -6,7 +6,7 @@
  * literal parts of skill/subagent names.
  */
 
-process.env.GSD_TEST_MODE = '1';
+process.env.MSD_TEST_MODE = '1';
 
 const { describe, test } = require('node:test');
 const assert = require('node:assert/strict');
@@ -17,7 +17,7 @@ const {
 } = require('../bin/install.js');
 const {
   _applyRuntimeRewrites,
-} = require('../gsd-core/bin/lib/runtime-artifact-conversion.cjs');
+} = require('../msd-core/bin/lib/runtime-artifact-conversion.cjs');
 
 describe('convertClaudeCommandToCursorSkill', () => {
   test('writes unquoted Cursor skill name in frontmatter', () => {
@@ -31,39 +31,39 @@ Test body
 </objective>
 `;
 
-    const result = convertClaudeCommandToCursorSkill(input, 'gsd-quick');
+    const result = convertClaudeCommandToCursorSkill(input, 'msd-quick');
     const nameMatch = result.match(/^name:\s*(.+)$/m);
 
     assert.ok(nameMatch, 'frontmatter contains name field');
-    assert.strictEqual(nameMatch[1], 'gsd-quick', 'skill name is plain scalar');
-    assert.ok(!result.includes('name: "gsd-quick"'), 'quoted skill name is not emitted');
+    assert.strictEqual(nameMatch[1], 'msd-quick', 'skill name is plain scalar');
+    assert.ok(!result.includes('name: "msd-quick"'), 'quoted skill name is not emitted');
   });
 
   test('preserves slash for slash commands in markdown body', () => {
     const input = `---
-name: gsd:plan-phase
+name: msd:plan-phase
 description: Plan a phase
 ---
 
 Next:
-/gsd:execute-phase 17
-/gsd-help
-gsd:progress
+/msd:execute-phase 17
+/msd-help
+msd:progress
 `;
 
-    const result = convertClaudeCommandToCursorSkill(input, 'gsd-plan-phase');
+    const result = convertClaudeCommandToCursorSkill(input, 'msd-plan-phase');
 
-    assert.ok(result.includes('/gsd-execute-phase 17'), 'slash command remains slash-prefixed');
-    assert.ok(result.includes('/gsd-help'), 'existing slash command is preserved');
-    assert.ok(result.includes('gsd-progress'), 'non-slash gsd: references still normalize');
-    assert.ok(!result.includes('/gsd:execute-phase'), 'legacy colon command form is removed');
+    assert.ok(result.includes('/msd-execute-phase 17'), 'slash command remains slash-prefixed');
+    assert.ok(result.includes('/msd-help'), 'existing slash command is preserved');
+    assert.ok(result.includes('msd-progress'), 'non-slash msd: references still normalize');
+    assert.ok(!result.includes('/msd:execute-phase'), 'legacy colon command form is removed');
   });
 });
 
 describe('convertClaudeAgentToCursorAgent', () => {
   test('writes unquoted Cursor agent name in frontmatter', () => {
     const input = `---
-name: gsd-planner
+name: msd-planner
 description: Planner agent
 tools: Read, Write
 color: green
@@ -78,8 +78,8 @@ Planner body
     const nameMatch = result.match(/^name:\s*(.+)$/m);
 
     assert.ok(nameMatch, 'frontmatter contains name field');
-    assert.strictEqual(nameMatch[1], 'gsd-planner', 'agent name is plain scalar');
-    assert.ok(!result.includes('name: "gsd-planner"'), 'quoted agent name is not emitted');
+    assert.strictEqual(nameMatch[1], 'msd-planner', 'agent name is plain scalar');
+    assert.ok(!result.includes('name: "msd-planner"'), 'quoted agent name is not emitted');
   });
 });
 
@@ -104,7 +104,7 @@ describe('_applyRuntimeRewrites(cursor) — bare-form ~/.claude regression (#135
   const COMPOUND_INPUT = [
     'Config dir: ~/.claude',
     'Also: $HOME/.claude',
-    'Slash form: ~/.claude/gsd-core/foo.md',
+    'Slash form: ~/.claude/msd-core/foo.md',
     'Inline: paths `~/.claude`, `~/.cursor`',
   ].join('\n');
 
@@ -137,10 +137,10 @@ describe('_applyRuntimeRewrites(cursor) — bare-form ~/.claude regression (#135
     );
   });
 
-  test('trailing-slash ~/.claude/gsd-core/foo.md is rewritten exactly once (no doubling)', () => {
-    const input = '~/.claude/gsd-core/foo.md';
+  test('trailing-slash ~/.claude/msd-core/foo.md is rewritten exactly once (no doubling)', () => {
+    const input = '~/.claude/msd-core/foo.md';
     const result = _applyRuntimeRewrites(input, 'cursor', CURSOR_PATH_PREFIX);
-    assert.ok(result.includes('~/.cursor/gsd-core/foo.md'), `slash form must be rewritten; got: ${result}`);
+    assert.ok(result.includes('~/.cursor/msd-core/foo.md'), `slash form must be rewritten; got: ${result}`);
     assert.ok(!result.includes('cursor/cursor'), `path must not be doubled; got: ${result}`);
     assert.ok(!result.includes('.claude'), `no .claude must survive; got: ${result}`);
   });