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)

get-shit-done/workflows/quick.md

@@ -129,7 +129,7 @@ if ! command -v gsd-sdk &>/dev/null; then
   echo "⚠ gsd-sdk not found in PATH — /gsd:quick requires it."
   echo ""
   echo "Install the query-capable GSD SDK CLI:"
-  echo "  npm install -g get-shit-done-cc"
+  echo "  npm install -g get-shit-done-redux"
   echo ""
   echo "Or update GSD to get the latest packages:"
   echo "  /gsd:update"