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/quick-mode.md

@@ -4,9 +4,9 @@ title: Quick Mode
 group: Planning Features
 ---
 
-**Command:** `/gsd-quick [--full] [--discuss] [--research]`
+**Command:** `/msd-quick [--full] [--discuss] [--research]`
 
-**Purpose:** Ad-hoc task execution with GSD guarantees but a faster path.
+**Purpose:** Ad-hoc task execution with MSD guarantees but a faster path.
 
 **Requirements:**
 - REQ-QUICK-01: System MUST accept freeform task description