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/workstream-inventory-builder.cts

@@ -379,7 +379,7 @@ export function buildWorkstreamInventory(inputs: BuildWorkstreamInventoryInputs)
   //    archived milestone. But a live in-milestone directory means the archive
   //    is NOT clean — a phase was added or reopened after it, reachable because
   //    `milestone complete` does not advance STATE's `milestone:` field
-  //    (state-transition.cts:83, :1335); only `/gsd-new-milestone` does (:1224).
+  //    (state-transition.cts:83, :1335); only `/msd-new-milestone` does (:1224).
   //    Once any in-milestone directory is live the ratio IS meaningful again, so
   //    the check is the conjunction. Requiring the live directory to itself be
   //    unfinished was too narrow: it let a complete live dir alongside a
@@ -450,7 +450,7 @@ export function buildWorkstreamInventory(inputs: BuildWorkstreamInventoryInputs)
     // with a `Scope` field and `WorkstreamInventory.progress_percent`'s type
     // from `number` to `number | null` — the exact "re-architecting
     // StateProjection/WorkstreamInventory return types" the design phase
-    // (`.gsd/phase/refactor-3217-completion-ratio-scoping/40-design.md`,
+    // (`.msd/phase/refactor-3217-completion-ratio-scoping/40-design.md`,
     // "Known limits") states is OUT of this phase's scope; or (b) silently
     // reusing `milestoneScoped` as a `Scope` stand-in, which would be exactly
     // the kind of proxy-for-a-data-flow-property this same phase's guard