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/features/codebase-mapping.md

@@ -4,15 +4,15 @@ title: Codebase Mapping
 group: Brownfield Features
 ---
 
-**Command:** `/gsd-map-codebase [area]`
+**Command:** `/msd-map-codebase [area]`
 
-**Purpose:** Analyze an existing codebase before starting a new project or as the mapping handoff from `/gsd-onboard`, so GSD understands what exists.
+**Purpose:** Analyze an existing codebase before starting a new project or as the mapping handoff from `/msd-onboard`, so MSD understands what exists.
 
 **Requirements:**
 - REQ-MAP-01: System MUST spawn parallel mapper agents for each analysis area
 - REQ-MAP-02: System MUST produce structured documents in `.planning/codebase/`
 - REQ-MAP-03: System MUST detect: tech stack, architecture patterns, coding conventions, concerns
-- REQ-MAP-04: Subsequent `/gsd-new-project` MUST load codebase mapping and focus questions on what's being added
+- REQ-MAP-04: Subsequent `/msd-new-project` MUST load codebase mapping and focus questions on what's being added
 - REQ-MAP-05: Optional `[area]` argument MUST scope mapping to a specific area
 
 **Produces:**