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/external-code-review-command.md

@@ -4,9 +4,9 @@ title: External Code Review Command
 group: v1.36.0 Features
 ---
 
-**Command:** `/gsd-ship` (enhanced)
+**Command:** `/msd-ship` (enhanced)
 
-**Purpose:** Before the manual review step in `/gsd-ship`, automatically run an external code review command if configured. The command receives the diff and phase context via stdin and returns a JSON verdict (`APPROVED` or `REVISE`). Falls through to the existing manual review flow regardless of outcome.
+**Purpose:** Before the manual review step in `/msd-ship`, automatically run an external code review command if configured. The command receives the diff and phase context via stdin and returns a JSON verdict (`APPROVED` or `REVISE`). Falls through to the existing manual review flow regardless of outcome.
 
 **Requirements:**
 - REQ-EXTREVIEW-01: `workflow.code_review_command` must be set to a command string; null means skip