chore: rebrand to GSD-redux/get-shit-done-redux

Mirror of code, issues, and PRs from the upstream gsd-build/get-shit-done,
which appears compromised or abandoned (maintainer unreachable since
2026-04-01; $GSD token linked to rug-pull).

- Adds rebrand notice block at top of English README
- Removes $GSD token badge and @gsd_foundation X badge (keeps Discord)
- Renames npm packages: get-shit-done-cc -> get-shit-done-redux,
  @gsd-build/sdk -> @gsd-redux/sdk
- Updates all repo URLs across docs, workflows, package.json, bin/
- Updates ci@gsd-build -> ci@gsd-redux in workflow git identities
- Leaves CHANGELOG and .changeset/* alone (historical, time-stamped)

sdk/src/sdk-package-compatibility.ts

@@ -113,7 +113,7 @@ function missingLegacyCoreMessage(resolution: LegacySdkAssetResolution): string
   return [
     'state load: get-shit-done/bin/lib/core.cjs not found.',
     `Checked: ${resolution.probes.join(', ')}`,
-    'Install GSD (e.g. npm i -g get-shit-done-cc) or clone with get-shit-done next to the SDK.',
+    'Install GSD (e.g. npm i -g get-shit-done-redux) or clone with get-shit-done next to the SDK.',
   ].join(' ');
 }