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)

docs/discussions/grok-build-support-2026-05.md

@@ -28,7 +28,7 @@ Currently, Grok Build is only supported via its Claude compatibility layer. This
 ## 2. Current Multi-Runtime Setup (as of May 2026)
 
 ### Development Source (Single Source of Truth)
-- **Path:** `/home/cristian/bum/get-shit-done` (this repo — your working fork of `gsd-build/get-shit-done`)
+- **Path:** `/home/cristian/bum/get-shit-done` (this repo — your working fork of `GSD-redux/get-shit-done-redux`)
 
 ### Installed Locations
 - `~/.agents/get-shit-done/` — Core workflows, references, templates, `gsd-tools.cjs`, `bin/`