Adapt to existing beos table in database sternwarte

Column mapping: id, name/vorname, kürzel (with umlaut), pw instead of
the planned schema. DB_NAME changed to sternwarte. create_table.sql
no longer creates beos, only the three new logbuch tables.

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

app/change-password/actions.ts

@@ -25,7 +25,7 @@ export async function changePassword(
 
   const hashed = await hashPassword(newPassword);
   await query(
-    'UPDATE beos SET Passwort = ?, MustChangePassword = 0 WHERE ID = ?',
+    'UPDATE beos SET pw = ?, MustChangePassword = 0 WHERE id = ?',
     [hashed, session.beoId]
   );