release(v1.7.0-alpha): bump + fix git-method update + reconciler creates

Two fixes bundled into the OTA:

1. update.download hard-fail on git-path nodes. handle_update_check's git
   branch reported update_available=true + update_method="git" but never
   populated state.available_update, so update.download returned "No update
   available to download" even though the UI showed one. SystemUpdate.vue
   now routes update_method=="git" through update.git-apply (pull+rebuild+
   restart via self-update.sh); manifest-path nodes keep the download→apply
   flow. i18n strings + confirm modal added for the git path.

2. Reconciler creating containers behind the user's back. On fresh
   unbundled installs (.198, .253) archy-mempool-db and archy-btcpay-db
   materialised ~10 min after first boot because reconcile-containers.sh
   walked container-specs.sh's canonical tier list and created any
   "missing" container. reset_spec() now defaults SPEC_OPTIONAL="true",
   so reconcile is strictly a repair tool — baseline comes from
   first-boot-containers.sh (filebrowser on unbundled), everything else
   from the install RPC.

Also forces OTA trigger for nodes on 1.6.0-alpha that otherwise saw
"I'm at manifest.version, nothing to do" and skipped the refreshed 1.6
artifacts.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

core/Cargo.lock

@@ -80,7 +80,7 @@ checksum = "a23eb6b1614318a8071c9b2521f36b424b2c83db5eb3a0fead4a6c0809af6e61"
 
 [[package]]
 name = "archipelago"
-version = "1.6.0-alpha"
+version = "1.7.0-alpha"
 dependencies = [
  "anyhow",
  "archipelago-container",