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.

src/token-scanner.cts

@@ -2,7 +2,7 @@
  * token-scanner.cts — the tokenizer-first seam for stateful grammars (ADR-3212
  * §4, epic #3212 Phase 3, #3414).
  *
- * Source in src/token-scanner.cts, compiled to gsd-core/bin/lib/token-scanner.cjs
+ * Source in src/token-scanner.cts, compiled to msd-core/bin/lib/token-scanner.cjs
  * (gitignored), per the repo's ADR-457 build-at-publish convention.
  *
  * Generalizes the proven `hooks/lib/git-cmd.js` token-walk (#3129 — "has not
@@ -16,7 +16,7 @@
  * decision, indented deeper than it), and a per-line regex cannot see that
  * nesting — only tracking indentation relative to the currently-open
  * decision can (ADR §4 criterion 1). See
- * .gsd/phase/chore-3414-tokenizer-first-seam/40-design.md §1.3 for the
+ * .msd/phase/chore-3414-tokenizer-first-seam/40-design.md §1.3 for the
  * disproven bold-run-content-classification alternative and why nesting
  * depth, not bullet content, is the actual distinguishing signal.
  */