Memberships: groups kept by portal itself, a person by phone number first

A membership is a case in the built-in portal_memberships bucket:
invited by a desk, a grants, the seed or the responsible pass; active
from the person's first sign-in, when the provider's subject, phone
number or address matches the record; removed by a desk, and invited
again after that. One record per group and person however it was
keyed, and at sign-in every record that matched learns what the
provider verified. The active memberships join the groups claim, so
Cedar sees the same parents as before.

PEOPLE_BACKEND picks Kanidm or memberships; unset, a KANIDM_API_TOKEN
means Kanidm. The NATS access service looks a person's groups up when
a question names them by sub, phone or email and lists none. The
sign-in asks for the phoneNumber scope and reads it from userinfo.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GT37Z1Xtfd9pUuQtMTg6Yt

src/mail.rs

@@ -565,7 +565,7 @@ pub async fn on_invite(state: &crate::server::AppState, invited: &crate::people:
         ),
         (None, false, true) => (
             "Du har fått plass i {group} på {site_name}".to_string(),
-            "Hei {name},\n\nKontoen din på {site} har nå plass i {group}. Logg inn som vanlig.".to_string(),
+            "Hei {name},\n\nDu har fått plass i {group} på {site_name}. Logg inn på {site}, så er plassen din der.".to_string(),
         ),
         (None, true, false) => (
             "You are invited into {group} at {site_name}".to_string(),
@@ -573,7 +573,7 @@ pub async fn on_invite(state: &crate::server::AppState, invited: &crate::people:
         ),
         (None, false, false) => (
             "You now have a place in {group} at {site_name}".to_string(),
-            "Hello {name},\n\nYour account at {site} now has a place in {group}. Sign in as usual.".to_string(),
+            "Hello {name},\n\nYou now have a place in {group} at {site_name}. Sign in at {site}, and it is there.".to_string(),
         ),
     };
     let now_ms = chrono::Utc::now().timestamp_millis();