feat: federation panel + Dart SDK federation methods (0.70.0)

A new 'Föderation' destination (primary side) lists connected
satellites — name, region, version, wire version, advertised
capabilities — and adds them in one step: 'Add satellite' issues a
single-use bootstrap token bundled with the primary CA as a
ready-to-paste satellite config (the bundled CA makes the first
connect tamper-proof). Localized EN + DE, in-app help doc. Uses the
new HubService.listSatellites / issueSatelliteToken wrapping the
SDK's federation methods.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

CHANGELOG.md

@@ -3,6 +3,20 @@
 All notable changes to `fai_studio` recorded here. Pubspec
 version + `kStudioVersion` in `lib/main.dart` stay in lockstep.
 
+## 0.70.0 — 2026-06-13
+
+### Added
+
+- **Federation panel.** A new "Föderation" destination shows the
+  satellites connected to this hub (name, region, version, wire
+  version, advertised capabilities) and adds them in one step: press
+  **Add satellite**, name it, and the hub issues a single-use
+  bootstrap token bundled with its CA as a ready-to-paste satellite
+  config — the bundled CA makes the satellite's first connect
+  tamper-proof. Localized (EN + DE) with an in-app help doc. Backed
+  by new `HubClient.listSatellites` / `issueBootstrapToken` in the
+  Dart SDK.
+
 ## 0.68.0 — 2026-06-09
 
 ### Added