Connect the two tools: cross-nav links and Send to Scope Lock handoff

- Add a header link on each tool pointing to the other.
- Add a Send to Scope Lock button on Workshop clusters that carry a
  candidate solution tag. Writes the item to a shared localStorage
  queue (sde_scope_handoff_v1).
- Scope Lock drains that queue on load and adds each item to the
  Scope Boundary Board as unsorted, deduping by a deterministic id so
  a repeat send never creates a duplicate.
- No backend needed: both tools already share the same browser origin.
- Verified with a jsdom test covering send, drain, reload, and
  re-send-after-reset.
- Update README and CHANGELOG.

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to this project are logged here, newest first. This file starts from the point the toolkit was handed off and set up in this repo.
 
+## 2026-09-04 (2)
+
+- Added: the two tools now work together. Each tool's header has a link to the other tool. On the Field Problem Workshop, a cluster tagged with a candidate solution (for example "Tracking MVP (pilot)") gets a "Send to Scope Lock" button. Clicking it adds that cluster as a real, unsorted item on the Scope Lock Meeting Suite's Scope Boundary Board. Both tools already share the same browser origin, so this uses a small shared `localStorage` queue; no backend or database was needed. The item lands on Scope Lock's board the next time that tool is opened or refreshed, and re-sending the same cluster will not create a duplicate. Verified with a jsdom test that simulates both tools sharing one browser's storage.
+
 ## 2026-09-04
 
 - Fixed: Portainer stack deploy failed with `env file /data/compose/44/.env not found`. Cause: `docker-compose.yml` used `env_file: - .env`, which requires a real file on disk; Portainer's UI-entered environment variables satisfy `${VAR}` substitution in the compose file but do not create that file. Changed `docker-compose.yml` to reference each setting as `${VAR:-default}` under `environment:` instead, which works both for a real local `.env` (auto-loaded by Compose for substitution) and for values entered directly in Portainer. Corrected the wrong explanation of this in `PORTAINER_DEPLOY.md`.