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.

hooks/msd-cursor-session-start.js

@@ -0,0 +1,57 @@
+#!/usr/bin/env node
+// msd-hook-version: {{MSD_VERSION}}
+// msd-cursor-session-start.js — Cursor sessionStart hook (issue #777)
+//
+// Cursor invokes this script at the start of each agent session.
+// Protocol: JSON from Cursor on stdin; JSON response on stdout.
+//
+// Input schema (cursor sessionStart):
+//   { session_id, is_background_agent, composer_mode, conversation_id,
+//     generation_id, model, hook_event_name, cursor_version,
+//     workspace_roots, user_email, transcript_path }
+//
+// Output schema (cursor sessionStart):
+//   { additional_context?: string }   ← injected into the session as context
+//
+// Behaviour:
+//   - If .planning/STATE.md is present, injects a brief state reminder.
+//   - If absent, nudges the user toward /msd:new-project.
+//   - Fails open: any error silently exits 0 so a hook bug never wedges Cursor.
+//
+// Cursor docs: https://cursor.com/docs/hooks
+
+'use strict';
+
+const fs = require('fs');
+const { allow } = require('./lib/hook-exit.js');
+
+const MSG_PRESENT =
+  'MSD: .planning/STATE.md is present — review the current phase and any blockers before acting.';
+const MSG_ABSENT =
+  'MSD: no .planning/ workflow found — run /msd:new-project to start a tracked workflow.';
+
+// Workspace resolution is shared across the Cursor hooks (#2587) — see
+// hooks/lib/cursor-workspace.js. Staged next to these scripts by
+// writeCursorHooksJson so the require always resolves post-install.
+const { resolveStatePath } = require('./lib/cursor-workspace.js');
+
+let raw = '';
+const stdinTimeout = setTimeout(() => {
+  // Timeout guard: exit silently rather than hanging.
+  allow(undefined);
+}, 10000);
+
+process.stdin.setEncoding('utf8');
+process.stdin.on('data', (chunk) => { raw += chunk; });
+process.stdin.on('end', () => {
+  clearTimeout(stdinTimeout);
+  try {
+    const statePath = resolveStatePath(raw);
+    const statePresent = fs.existsSync(statePath);
+    const msg = statePresent ? MSG_PRESENT : MSG_ABSENT;
+    process.stdout.write(JSON.stringify({ additional_context: msg }));
+  } catch {
+    // Fail open — never block a Cursor session because of a MSD hook error.
+    process.stdout.write(JSON.stringify({}));
+  }
+});