feat: email verification for registration, email change, and invitations

Registration now creates a pending account and sends a 6-digit code via
email; the account activates only after verification. Email changes on
the profile page follow the same flow. Group invitations send a
notification email to the invitee (without revealing their address to
the inviter) containing the invite code and hub link.

Backend: blind HMAC-SHA256 email index for uniqueness without decryption,
mail.py for localhost Postfix delivery, verification endpoints, cleanup
of expired codes and stale pending accounts, startup backfill of
email_hash for existing users.

Frontend: 3-phase register page, inline email change verification on
profile, invite-notify call with status display. All 10 locales updated.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/group-settings.js b/packages/meshbay-hub/src/meshbay_hub/static/group-settings.js
index 4f55dfb..1c6ca71 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/group-settings.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/group-settings.js
@@ -793,7 +793,21 @@ function GroupSettingsPanel({ groupId, group, token, transportRef, gekRef,
         method: 'POST', token, body: {},
       });
 
-      setInviteCode({ username, code: result.code, expires: result.expires_at });
+      // Send an email notification to the invitee with the code.
+      // The hub decrypts their email server-side — the inviter never sees it.
+      let emailStatus = 'no_email';
+      try {
+        const notif = await hubFetch(`/v1/groups/${groupId}/invite-notify`, {
+          method: 'POST', token,
+          body: { username, code: result.code, group_name: group?.name || '' },
+        });
+        emailStatus = notif.status;
+      } catch { /* best effort */ }
+
+      setInviteCode({
+        username, code: result.code, expires: result.expires_at,
+        emailSent: emailStatus === 'sent',
+      });
       setInviteUser('');
       loadMembers();
     } catch (err) {
@@ -831,6 +845,10 @@ function GroupSettingsPanel({ groupId, group, token, transportRef, gekRef,
               <div class="success-msg" style="margin-bottom:8px">
                 <p>${t('members.invite_code_ready', { user: inviteCode.username })}</p>
                 <p class="code-display">${inviteCode.code}</p>
+                ${inviteCode.emailSent
+                  ? html`<p style="color:var(--success)">${t('members.invite_email_sent')}</p>`
+                  : html`<p style="color:var(--text-dim)">${t('members.invite_email_failed')}</p>`
+                }
                 <p>${t('members.invite_code_hint')}</p>
               </div>
             `}