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/context-predicates.property.test.cjs

@@ -2,7 +2,7 @@
 
 /**
  * Property-based tests for src/context-predicates.cts (compiled to
- * gsd-core/bin/lib/context-predicates.cjs).
+ * msd-core/bin/lib/context-predicates.cjs).
  *
  * Document-shaped generators (CONTRIBUTING.md "Fixture provenance #2371"):
  * these generators build arbitrary markdown documents out of prose lines,
@@ -21,7 +21,7 @@ const { describe, test } = require('node:test');
 const assert = require('node:assert/strict');
 const fc = require('./helpers/fast-check-setup.cjs');
 
-const { parsePredicates, selectPredicates, buildIndex } = require('../gsd-core/bin/lib/context-predicates.cjs');
+const { parsePredicates, selectPredicates, buildIndex } = require('../msd-core/bin/lib/context-predicates.cjs');
 
 // ─── Document-shaped generators ────────────────────────────────────────────