chore(#516): single-source the package name from package.json (#517)

Adds get-shit-done/bin/lib/package-identity.cjs as the single source of
truth for PACKAGE_NAME, derived from package.json `name` via require.
Refactors all runtime code-line occurrences in bin/install.js,
get-shit-done/bin/check-latest-version.cjs,
get-shit-done/bin/lib/shell-command-projection.cjs,
get-shit-done/bin/lib/verify.cjs, scripts/changeset/cli.cjs,
scripts/changeset/github-release-notes.cjs, and
scripts/release-tarball-smoke.cjs to import PACKAGE_NAME from the
identity module instead of hardcoding the literal.

The package name is unchanged (@opengsd/get-shit-done-redux). Behaviour
is byte-identical: all --help, hint, and release-notes strings render
exactly as before. Golden-literal tests (bug-2992, bug-378) keep their
hardcoded expected values and remain GREEN.

Adds tests/package-name-single-source.test.cjs lint guard: fails CI if
@opengsd/get-shit-done-redux appears as a code-line literal in runtime
.cjs/.js outside the identity module, enforcing a one-file rename path.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

scripts/changeset/cli.cjs

@@ -25,6 +25,7 @@ const {
   compareSemverCore,
   isStableTripletSemver,
 } = require('../../get-shit-done/bin/lib/semver-compare.cjs');
+const { PACKAGE_NAME } = require('../../get-shit-done/bin/lib/package-identity.cjs');
 
 function parseArgs(argv) {
   const opts = {
@@ -37,7 +38,7 @@ function parseArgs(argv) {
     changelog: null,
     output: null,
     repoSlug: 'open-gsd/get-shit-done-redux',
-    installCommand: 'npx @opengsd/get-shit-done-redux@latest',
+    installCommand: `npx ${PACKAGE_NAME}@latest`,
     json: false,
   };
   if (argv.length === 0) return { ok: true, opts };

scripts/changeset/github-release-notes.cjs

@@ -4,6 +4,7 @@ const cp = require('node:child_process');
 const path = require('node:path');
 
 const { parseFragment } = require('./parse.cjs');
+const { PACKAGE_NAME } = require('../../get-shit-done/bin/lib/package-identity.cjs');
 
 const SECTION_ORDER = ['Fixed', 'Added', 'Changed', 'Deprecated', 'Removed', 'Security'];
 
@@ -146,7 +147,7 @@ function serializeGithubReleaseNotes({
   fromRef,
   toRef,
   repoSlug = 'open-gsd/get-shit-done-redux',
-  installCommand = 'npx @opengsd/get-shit-done-redux@latest',
+  installCommand = `npx ${PACKAGE_NAME}@latest`,
 }) {
   if (installCommand.includes('`')) {
     throw new Error('installCommand cannot contain backtick characters');

scripts/release-tarball-smoke.cjs

@@ -45,6 +45,7 @@ const { execFileSync, spawnSync } = require('child_process');
 const fs = require('fs');
 const os = require('os');
 const path = require('path');
+const { PACKAGE_NAME } = require('../get-shit-done/bin/lib/package-identity.cjs');
 // 120 s proved too tight on Windows GitHub-hosted runners: cold-cache
 // `npm install -g` with a 1499-file tarball took ~120 s exactly, causing
 // spawnSync to fire SIGTERM and return { status: null, stdout: '', stderr: '' }
@@ -121,10 +122,12 @@ function binInvocation(binPath, args = []) {
  * an npm --prefix install directory.
  */
 function pkgRoot(installPrefix) {
-  // POSIX: <prefix>/lib/node_modules/@opengsd/get-shit-done-redux
-  // Windows: <prefix>/node_modules/@opengsd/get-shit-done-redux
-  const posix = path.join(installPrefix, 'lib', 'node_modules', '@opengsd', 'get-shit-done-redux');
-  const win = path.join(installPrefix, 'node_modules', '@opengsd', 'get-shit-done-redux');
+  // POSIX: <prefix>/lib/node_modules/<scope>/<pkg>
+  // Windows: <prefix>/node_modules/<scope>/<pkg>
+  // PACKAGE_NAME is scoped (@scope/pkg), so split('/') yields the two path segments.
+  const pkgSegments = PACKAGE_NAME.split('/');
+  const posix = path.join(installPrefix, 'lib', 'node_modules', ...pkgSegments);
+  const win = path.join(installPrefix, 'node_modules', ...pkgSegments);
   return fs.existsSync(posix) ? posix : win;
 }