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/verify-command-grounding.cts

@@ -949,7 +949,7 @@ const DEFAULT_LOOKBACK = 3;
  *
  * Phase directories are enumerated and ordered via the canonical grammar in
  * `phase-id.cjs` (#2401 review fix) rather than a bespoke `phase-N-slug`
- * regex — real GSD phase directories are `01-foundation`, `3-thing`,
+ * regex — real MSD phase directories are `01-foundation`, `3-thing`,
  * `2.1-thing`, `12A-thing`, or project-code-prefixed (`CK-01-name`), never
  * `phase-N-slug`. A directory name is treated as a phase directory only when
  * it (after stripping an optional project-code prefix) starts with a digit;