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/decisions.cts

@@ -225,7 +225,7 @@ const boldLeadInBulletRe = /^\s*-\s+\*\*[A-Z]+[0-9]*-[A-Za-z0-9]/m;
 /**
  * #3939: a decision bullet's DECLARATION line — the `- **D[phase]-NN … **` bold
  * lead-in the three grammars above anchor on — may wrap across a line break.
- * Physical line breaks inside a bullet are markdown-insignificant, and GSD's own
+ * Physical line breaks inside a bullet are markdown-insignificant, and MSD's own
  * discuss-phase writer emits the wrapped shape whenever a decision title runs
  * past the wrap column. All three grammars require the closing `**` in the same
  * string as the `- **D…-` anchor, so a wrapped declaration matched none of them
@@ -501,7 +501,7 @@ function parseDecisionLines(block: string): ParseDecisionLinesResult {
     // like a continuation line, before it ever reaches the declaration/
     // parse-miss regexes below. A bullet at the SAME or a SHALLOWER indent
     // is unaffected — tested exactly as before this fix. See design doc
-    // .gsd/phase/chore-3414-tokenizer-first-seam/40-design.md §1.3 for why
+    // .msd/phase/chore-3414-tokenizer-first-seam/40-design.md §1.3 for why
     // nesting depth, not bullet content, is the signal that distinguishes
     // this from a genuinely malformed top-level declaration.
     if (