chore(deps): update nixpkgs to nixos-26.05 and flake inputs

flake.nix

@@ -14,7 +14,7 @@
     multigres.url = "github:multigres/multigres";
     multigres.flake = false;
     nix-darwin.inputs.nixpkgs.follows = "nixpkgs";
-    nix-darwin.url = "github:nix-darwin/nix-darwin";
+    nix-darwin.url = "github:nix-darwin/nix-darwin/nix-darwin-26.05";
     nix-editor.inputs.nixpkgs.follows = "nixpkgs";
     nix-editor.inputs.utils.follows = "flake-utils";
     nix-editor.url = "github:snowfallorg/nix-editor";
@@ -23,10 +23,9 @@
     nix-eval-jobs.url = "github:nix-community/nix-eval-jobs";
     nix2container.inputs.nixpkgs.follows = "nixpkgs";
     nix2container.url = "github:nlewo/nix2container";
-    # Pin to a specific nixpkgs version that has compatible v8 and curl versions
-    # for extensions that require older package versions
+    # Pin to a specific nixpkgs version that still has the v8 version plv8 needs
     nixpkgs-oldstable.url = "github:NixOS/nixpkgs/a76c4553d7e741e17f289224eda135423de0491d";
-    nixpkgs.url = "https://channels.nixos.org/nixos-unstable/nixexprs.tar.xz";
+    nixpkgs.url = "https://channels.nixos.org/nixos-26.05/nixexprs.tar.xz";
     rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
     rust-overlay.url = "github:oxalica/rust-overlay";
     treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";

nix/cargo-pgrx/default.nix

@@ -1,6 +1,5 @@
 {
   lib,
-  pkgs,
   fetchCrate,
   openssl,
   pkg-config,
@@ -10,11 +9,10 @@
   rustVersion ? "1.85.1",
 }:
 let
-  # TODO: remove once nixpkgs is bumped past NixOS/nixpkgs#512735
-  rustPlatform = import ./fix-cargo.nix { inherit pkgs; } (makeRustPlatform {
+  rustPlatform = makeRustPlatform {
     cargo = rust-bin.stable.${rustVersion}.default;
     rustc = rust-bin.stable.${rustVersion}.default;
-  });
+  };
 in
 {
   mkCargoPgrx =
@@ -34,11 +32,7 @@ in
       auditable = false;
       inherit pname;
       inherit version;
-      # TODO: remove once nixpkgs is bumped past NixOS/nixpkgs#512735
-      src = fetchCrate {
-        inherit version pname hash;
-        registryDl = "https://static.crates.io/crates";
-      };
+      src = fetchCrate { inherit version pname hash; };
       inherit cargoHash;
       nativeBuildInputs = lib.optionals stdenv.hostPlatform.isLinux [ pkg-config ];
       buildInputs = lib.optionals stdenv.hostPlatform.isLinux [ openssl ];