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)

.github/pull_request_template.md

@@ -17,7 +17,7 @@ Select the template that matches your PR:
 - If it **corrects broken behavior** → Fix
 - If it **improves existing behavior** without adding new commands or concepts → Enhancement
 - If it **adds something that doesn't exist today** → Feature
-- If you are not sure → open a [Discussion](https://github.com/gsd-build/get-shit-done/discussions) first
+- If you are not sure → open a [Discussion](https://github.com/GSD-redux/get-shit-done-redux/discussions) first
 
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