Fix agenix-rekey: add real uConsole host key, re-encrypt secrets

- Update uConsole hostPubkey from dummy to real SSH host key
- Add uConsole host key to keys.nix
- Add age.rekey config to lazyworkhorse
- Add SSH host key to identityPaths on both hosts
- Re-encrypt builder_key.age and gortium_password.age for both hosts

lib/keys.nix

@@ -25,5 +25,9 @@
       gitea = "";
       bootstrap = "age1r796v2uldtspawyh863pks74sd2pwcan8j4e4pjzsvkmr3vjja9qpz5ste";
     };
+    uConsole = {
+      main = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICasvsmaHuNVaWnjwuBfoMXyY/6PIqGL8yxstPBb46u4";
+      bootstrap = "age1un8td4jzkhg5fm4jja7z3aznskc8hlcm8ky0j2f70tv74rulwgaqtpemn2";
+    };
   };
 }