Remove API key requirement

nix/package.nix

@@ -15,9 +15,6 @@
   curl,
   openssl,
   systemdLibs,
-  # Portal API key baked into the binary. Keep it out of the flake; pass it
-  # when calling callPackage from CI/your own config (see README "App version").
-  apiKey ? "",
   # App version baked into the Home footer's Version row. CI overrides this
   # per branch (git tag on main, commit hash on dev); local/pure builds keep
   # the 0.1.0 default.
@@ -54,10 +51,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   # Bake the package version into the binary so the Home footer's Version row
   # shows it (CMake passes APP_VERSION through as a compile definition).
-  # API_KEY is only added when a non-empty key is supplied to callPackage.
-  cmakeFlags =
-    [ "-DAPP_VERSION=${finalAttrs.version}" ]
-    ++ lib.optionals (apiKey != "") [ "-DAPI_KEY=${apiKey}" ];
+  cmakeFlags = [ "-DAPP_VERSION=${finalAttrs.version}" ];
 
   # gtest is a buildInput, not native: nixpkgs builds it shared, so the
   # check-phase test binaries need its lib dir baked into their RPATH.