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/fallow-runner.test.cjs

@@ -8,10 +8,10 @@ const fs = require('node:fs');
 const {
   resolveFallowBinary,
   requireFallowBinary,
-} = require(path.join(__dirname, '..', 'gsd-core', 'bin', 'lib', 'fallow-runner.cjs'));
+} = require(path.join(__dirname, '..', 'msd-core', 'bin', 'lib', 'fallow-runner.cjs'));
 const {
   resolveExecutableBinary,
-} = require(path.join(__dirname, '..', 'gsd-core', 'bin', 'lib', 'shell-command-projection.cjs'));
+} = require(path.join(__dirname, '..', 'msd-core', 'bin', 'lib', 'shell-command-projection.cjs'));
 
 const { createTempDir, cleanup } = require('./helpers.cjs');
 
@@ -36,7 +36,7 @@ const FALLOW_FIXTURE = process.platform === 'win32' ? `fallow${WIN32_CMD_EXT}` :
 
 // ─── fallow-runner (#3618 Phase 2) ──────────────────────────────────────────
 // Fold of the prior private resolver onto the seam's resolveExecutableBinary.
-// See .gsd/phase/chore-3618-fallow-binary-resolution/50-test-matrix.md (F1-F15).
+// See .msd/phase/chore-3618-fallow-binary-resolution/50-test-matrix.md (F1-F15).
 //
 // Executability (X_OK) cannot be forced via chmod — root Docker bypasses mode
 // bits, which would silently zero out coverage. Every case that needs a POSIX