chore(devbox): update lock file with pinned dependency versions

Pin package versions from @latest to concrete versions for reproducible
development environments across the team.

Changes:
- go: latest → 1.25.1
- hugo: latest → 0.151.0
- nodejs: latest → 24.10.0
- Added nixpkgs-unstable entry (2025-10-20)

This ensures all developers use identical tool versions, improving
build reproducibility and reducing "works on my machine" issues.

devbox.lock

@@ -65,6 +65,10 @@
         }
       }
     },
+    "github:NixOS/nixpkgs/nixpkgs-unstable": {
+      "last_modified": "2025-10-20T13:06:07Z",
+      "resolved": "github:NixOS/nixpkgs/cb82756ecc37fa623f8cf3e88854f9bf7f64af93?lastModified=1760965567&narHash=sha256-0JDOal5P7xzzAibvD0yTE3ptyvoVOAL0rcELmDdtSKg%3D"
+    },
     "go-task@latest": {
       "last_modified": "2025-10-07T08:41:47Z",
       "resolved": "github:NixOS/nixpkgs/bce5fe2bb998488d8e7e7856315f90496723793c#go-task",
@@ -113,7 +117,7 @@
         }
       }
     },
-    "go@latest": {
+    "go@1.25.1": {
       "last_modified": "2025-10-07T08:41:47Z",
       "resolved": "github:NixOS/nixpkgs/bce5fe2bb998488d8e7e7856315f90496723793c#go",
       "source": "devbox-search",
@@ -209,7 +213,7 @@
         }
       }
     },
-    "hugo@latest": {
+    "hugo@0.151.0": {
       "last_modified": "2025-10-09T02:37:25Z",
       "resolved": "github:NixOS/nixpkgs/2dad7af78a183b6c486702c18af8a9544f298377#hugo",
       "source": "devbox-search",
@@ -257,7 +261,7 @@
         }
       }
     },
-    "nodejs@latest": {
+    "nodejs@24.10.0": {
       "last_modified": "2025-10-13T09:56:54Z",
       "plugin_version": "0.0.2",
       "resolved": "github:NixOS/nixpkgs/c12c63cd6c5eb34c7b4c3076c6a99e00fcab86ec#nodejs_24",