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.

docs/how-to/change-the-state-md-schema.md

@@ -36,14 +36,14 @@ npm run regen:derived
 ```
 
 **The order matters and getting it wrong fails quietly.** The generator reads the *compiled*
-`gsd-core/bin/lib/state-md-schema.cjs`, not the TypeScript source. Regenerating before building
+`msd-core/bin/lib/state-md-schema.cjs`, not the TypeScript source. Regenerating before building
 regenerates against the previous schema, produces artifacts that look plausible, and commits a
 document that disagrees with the code you just wrote. If you are ever unsure whether the build is
 current, run `npm run build:lib` again — it is cheap and idempotent.
 
 **3. Commit the regenerated artifacts.** They are generated *and committed*:
 
-- `gsd-core/templates/state.md`
+- `msd-core/templates/state.md`
 - `docs/reference/state-md.md` and its `ja-JP`, `zh-CN`, `ko-KR`, `pt-BR` siblings
 
 **4. Add the human-facing rows by hand.** Two tables in the reference documents are deliberately