Update flutter and devenv, set devenv to nixos-unstable

devenv.lock

@@ -3,10 +3,10 @@
     "devenv": {
       "locked": {
         "dir": "src/modules",
-        "lastModified": 1747717470,
+        "lastModified": 1753386188,
         "owner": "cachix",
         "repo": "devenv",
-        "rev": "c7f2256ee4a4a4ee9cbf1e82a6e49b253c374995",
+        "rev": "a19c43648f108256e442e46dc32d4eee57c71ac3",
         "type": "github"
       },
       "original": {
@@ -40,10 +40,10 @@
         ]
       },
       "locked": {
-        "lastModified": 1747372754,
+        "lastModified": 1750779888,
         "owner": "cachix",
         "repo": "git-hooks.nix",
-        "rev": "80479b6ec16fefd9c1db3ea13aeb038c60530f46",
+        "rev": "16ec914f6fb6f599ce988427d9d94efddf25fe6d",
         "type": "github"
       },
       "original": {
@@ -74,16 +74,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1746807397,
-        "owner": "cachix",
-        "repo": "devenv-nixpkgs",
-        "rev": "c5208b594838ea8e6cca5997fbf784b7cca1ca90",
+        "lastModified": 1753250450,
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "fc02ee70efb805d3b2865908a13ddd4474557ecf",
         "type": "github"
       },
       "original": {
-        "owner": "cachix",
-        "ref": "rolling",
-        "repo": "devenv-nixpkgs",
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
         "type": "github"
       }
     },