Step 4 (e) of ADR 0044, its first part, for every app's screens.
- halkyon_app: `SharedSpaceGateway` on the module's `sharedSpace`
endpoint (the spaces, their members and roles, inviting, handing on,
leaving), refusals as `SpaceRefused`; `SharedKeys.trustIn` gives
each member's safety code and whether it was compared or their keys
changed, `markCompared`, and `trustNewKeys`, which pins the keys
whose code was compared and never those the instance hands next.
`FakeSharedSpaceServer` keeps the module's rules for tests, in step
with `FakeSharedKeysServer`, which now knows members' handles.
- Learn's sharing makes its space through it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>