Configure the invitation mailbox in the UI, not the environment

Putting IMAP settings in environment variables was my call to make and it was
the wrong one: it meant editing a file on the server and restarting to change a
folder name, and it was never offered as a choice.

The mailbox is now a row in mailbox_accounts, edited under Settings → Admin:
host, user, password, port, folder, interval, on/off. Administrators only — it
is a shared forwarding target, not a per-user account. The password is never
returned by any endpoint, the same as the CalDAV account routes, and leaving
the field empty on edit keeps the stored one so changing a port does not mean
retyping it. The panel shows when the mailbox was last read and what went wrong
if it did, because a mailbox that quietly stopped working looks exactly like
one that has no mail.

Worth stating plainly: the password now lives in the database, in clear text,
like the CalDAV, Google and Home Assistant credentials beside it. Unlike those
three, an IMAP password opens an entire mailbox.

The scheduler job is registered unconditionally now — whether a mailbox exists
can change without a restart, and fetch_invites returns immediately when none
does. test_scheduler knows about it.

Also adds the requests list to the sidebar with accept and decline, 26
translation keys across all ten languages, and tests covering that the password
is never returned, that an edit without one keeps it, and that a disabled
mailbox counts as unconfigured.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/routers/invites_router.py

@@ -131,21 +131,134 @@ def dismiss(invite_id: int, db: Session = Depends(get_db),
 
 
 @router.get("/status")
-def status(current_user: models.User = Depends(get_current_user)):
-    return {"imap_configured": mail_invites.is_configured()}
+def status(db: Session = Depends(get_db),
+           current_user: models.User = Depends(get_current_user)):
+    acc = mail_invites.get_account(db)
+    return {
+        "imap_configured": acc is not None,
+        "smtp_configured": bool(acc and acc.smtp_host),
+        "last_run": acc.last_run.isoformat() if acc and acc.last_run else None,
+        "last_error": acc.last_error if acc else None,
+    }
+
+
+# ── Mailbox configuration ─────────────────────────────────
+#
+# One mailbox per instance: it is a shared forwarding target, not a per-user
+# account, so only administrators may see or change it.
+
+
+def _require_admin(user: models.User) -> None:
+    if not user.is_admin:
+        raise HTTPException(403, "Nur für Administratoren")
+
+
+def _mailbox_dict(acc) -> dict | None:
+    if acc is None:
+        return None
+    # Passwords are never returned, the same as the CalDAV account endpoints.
+    return {
+        "id": acc.id,
+        "enabled": bool(acc.enabled),
+        "imap_host": acc.imap_host,
+        "imap_port": acc.imap_port,
+        "imap_ssl": bool(acc.imap_ssl),
+        "imap_user": acc.imap_user,
+        "imap_folder": acc.imap_folder,
+        "poll_minutes": acc.poll_minutes,
+        "has_imap_password": bool(acc.imap_password),
+        "smtp_host": acc.smtp_host,
+        "smtp_port": acc.smtp_port,
+        "smtp_ssl": bool(acc.smtp_ssl),
+        "smtp_user": acc.smtp_user,
+        "smtp_from": acc.smtp_from,
+        "has_smtp_password": bool(acc.smtp_password),
+        "last_run": acc.last_run.isoformat() if acc.last_run else None,
+        "last_error": acc.last_error,
+    }
+
+
+class MailboxUpdate(BaseModel):
+    enabled: bool = True
+    imap_host: str
+    imap_port: int = 993
+    imap_ssl: bool = True
+    imap_user: str
+    # Optional on edit: left out keeps the stored one, so changing a port does
+    # not mean retyping the password.
+    imap_password: Optional[str] = None
+    imap_folder: str = "INBOX"
+    poll_minutes: int = 5
+    smtp_host: Optional[str] = None
+    smtp_port: Optional[int] = 587
+    smtp_ssl: Optional[bool] = False
+    smtp_user: Optional[str] = None
+    smtp_password: Optional[str] = None
+    smtp_from: Optional[str] = None
+
+
+@router.get("/mailbox")
+def get_mailbox(db: Session = Depends(get_db),
+                current_user: models.User = Depends(get_current_user)):
+    _require_admin(current_user)
+    return _mailbox_dict(
+        db.query(models.MailboxAccount).order_by(models.MailboxAccount.id).first())
+
+
+@router.put("/mailbox")
+def set_mailbox(data: MailboxUpdate, db: Session = Depends(get_db),
+                current_user: models.User = Depends(get_current_user)):
+    _require_admin(current_user)
+    acc = db.query(models.MailboxAccount).order_by(models.MailboxAccount.id).first()
+    if acc is None:
+        acc = models.MailboxAccount(imap_host="", imap_user="", imap_password="")
+        db.add(acc)
+
+    if not data.imap_password and not acc.imap_password:
+        raise HTTPException(422, "Passwort fehlt")
+    if not 1 <= data.poll_minutes <= 1440:
+        raise HTTPException(422, "Abrufintervall muss zwischen 1 und 1440 Minuten liegen")
+
+    acc.enabled = data.enabled
+    acc.imap_host = data.imap_host.strip()
+    acc.imap_port = data.imap_port
+    acc.imap_ssl = data.imap_ssl
+    acc.imap_user = data.imap_user.strip()
+    if data.imap_password:
+        acc.imap_password = data.imap_password
+    acc.imap_folder = (data.imap_folder or "INBOX").strip()
+    acc.poll_minutes = data.poll_minutes
+    acc.smtp_host = (data.smtp_host or "").strip() or None
+    acc.smtp_port = data.smtp_port
+    acc.smtp_ssl = bool(data.smtp_ssl)
+    acc.smtp_user = (data.smtp_user or "").strip() or None
+    if data.smtp_password:
+        acc.smtp_password = data.smtp_password
+    acc.smtp_from = (data.smtp_from or "").strip() or None
+    # Settings changed, so whatever went wrong before is no longer current.
+    acc.last_error = None
+    db.commit()
+    return _mailbox_dict(acc)
+
+
+@router.delete("/mailbox")
+def delete_mailbox(db: Session = Depends(get_db),
+                   current_user: models.User = Depends(get_current_user)):
+    _require_admin(current_user)
+    acc = db.query(models.MailboxAccount).order_by(models.MailboxAccount.id).first()
+    if acc:
+        db.delete(acc)
+        db.commit()
+    return {"ok": True}
 
 
 @router.post("/poll")
 def poll_now(db: Session = Depends(get_db),
              current_user: models.User = Depends(get_current_user)):
-    """Fetch right now instead of waiting for the scheduler.
-
-    Admin-only: it opens a connection to the shared mailbox, so it is not a
-    per-user action.
-    """
-    if not current_user.is_admin:
-        raise HTTPException(403, "Nur für Administratoren")
-    if not mail_invites.is_configured():
+    """Fetch right now instead of waiting for the scheduler."""
+    _require_admin(current_user)
+    if not mail_invites.is_configured(db):
         raise HTTPException(400, "Kein Postfach konfiguriert")
     mail_invites.fetch_invites(db)
-    return {"ok": True}
+    acc = mail_invites.get_account(db)
+    return {"ok": True, "last_error": acc.last_error if acc else None}