chore: update all packages to latest versions

- aionui 2.1.4 -> 2.1.50
- desloppify 0.9.15 -> 1.0
- ds4 -> 2026-08-05 (b030961)
- freebuff 0.0.85 -> 0.0.142 (binary moved to GitHub releases)
- graphify 0.7.10 -> 0.9.35 (license Apache-2.0, fix sed patterns for versioned deps)
- hipengine 0.2.2 -> 0.3.0 (console script renamed to hipengine)
- kubernetes-mcp-server 0.0.62 -> 0.0.66 (requires go >= 1.26.3)
- mcp-gateway 2.11.0 -> 3.4.0 (requires rustc >= 1.95)
- omniroute 3.8.28 -> 3.8.49
- radar 1.6.1 -> 1.9.1 (drop obsolete lockfile sed patch)
- relay-free-llm -> 96e6c48, cerebras-cloud-sdk 1.67.0 -> 1.91.0
- stakpak 0.3.86 -> 0.3.88

Add nixpkgs-latest input for toolchains newer than the pinned nixpkgs.

flake.lock

@@ -89,12 +89,29 @@
         "type": "github"
       }
     },
+    "nixpkgs-latest": {
+      "locked": {
+        "lastModified": 1785967620,
+        "narHash": "sha256-IItrdb7Puk05RqOBWZYFC5X6Wl1sJmCfh5MWVHw5iMM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "b7c2ada94fe99c15b0dbcf4d11fd7850b957a436",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "blueprint": "blueprint",
         "bun2nix": "bun2nix",
         "flake-parts": "flake-parts",
         "nixpkgs": "nixpkgs",
+        "nixpkgs-latest": "nixpkgs-latest",
         "systems": "systems",
         "treefmt-nix": "treefmt-nix"
       }