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/plan-scan.cts

@@ -86,7 +86,7 @@ function isRootPlanFile(fileName: string): boolean {
   // #3741: the PLAN token must be DELIMITED — anchored at the start or after
   // a hyphen, and followed only by an optional `-<digits>…` suffix before
   // `.md` (the `…` keeps the legacy slug form `3-PLAN-01-setup.md` that
-  // gsd-plan-phase writes, per #3128). A bare substring test counted
+  // msd-plan-phase writes, per #3128). A bare substring test counted
   // REPLAN-INPUTS / PLANNING-INPUTS / PLANNING-NOTES as plans, inflating
   // planCount and STATE.md's derived total_plans. Delimited keeps the
   // fallback's deliberate permissiveness for legacy single-token names