feat(crumb): Configure Firefox

- Set search engines.
- Install extensions
- Set basic Firefox settings.
- Bump home-manager to use updated `programs.firefox` API.  Namely,
  `programs.firefox.profiles.NAME.extensions`.

flake.lock

@@ -80,6 +80,27 @@
       }
     },
     "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nur",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1733312601,
+        "narHash": "sha256-4pDvzqnegAfRkPwO3wmwBhVi/Sye1mzps0zHWYnP88c=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "205b12d8b7cd4802fbcb8e8ef6a0f1408781a4f9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "flake-parts_2": {
       "inputs": {
         "nixpkgs-lib": "nixpkgs-lib"
       },
@@ -135,11 +156,11 @@
         "nixpkgs": "nixpkgs_3"
       },
       "locked": {
-        "lastModified": 1736441698,
-        "narHash": "sha256-0CpZ8xp6C9/k3KVul1xhsVOnPyYZ3OWp/6sA8WGOWM4=",
+        "lastModified": 1741376022,
+        "narHash": "sha256-EPMhteiZurPFiVs1ioBtiUgUMih52w3IwOWLV0hoX1w=",
         "owner": "msyds",
         "repo": "home-manager",
-        "rev": "71be4c32c349f3ea85cdfbe0f21c44357644fc91",
+        "rev": "7b87c2d8b9ad72e83402f8fc6dde24e76b28ee67",
         "type": "github"
       },
       "original": {
@@ -222,7 +243,7 @@
     },
     "nix-fetcher-data": {
       "inputs": {
-        "flake-parts": "flake-parts",
+        "flake-parts": "flake-parts_2",
         "nixpkgs": [
           "sydnix-cli",
           "clj-nix",
@@ -304,11 +325,11 @@
     },
     "nixpkgs_3": {
       "locked": {
-        "lastModified": 1736012469,
-        "narHash": "sha256-/qlNWm/IEVVH7GfgAIyP6EsVZI6zjAx1cV5zNyrs+rI=",
+        "lastModified": 1741010256,
+        "narHash": "sha256-WZNlK/KX7Sni0RyqLSqLPbK8k08Kq7H7RijPJbq9KHM=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "8f3e1f807051e32d8c95cd12b9b421623850a34d",
+        "rev": "ba487dbc9d04e0634c64e3b1f0d25839a0a68246",
         "type": "github"
       },
       "original": {
@@ -398,6 +419,28 @@
         "type": "github"
       }
     },
+    "nur": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "treefmt-nix": "treefmt-nix"
+      },
+      "locked": {
+        "lastModified": 1741373419,
+        "narHash": "sha256-RkLmZob4GnlKntjO26io6wf6haE24pcTr3jAljMJ45c=",
+        "owner": "nix-community",
+        "repo": "NUR",
+        "rev": "4463e6382eca077dbd3c74ae336aef516221b4fc",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "NUR",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "copyparty": "copyparty",
@@ -406,6 +449,7 @@
         "impermanence": "impermanence",
         "niri": "niri",
         "nixpkgs": "nixpkgs_5",
+        "nur": "nur",
         "sops-nix": "sops-nix",
         "sydnix-cli": "sydnix-cli"
       }
@@ -460,6 +504,27 @@
         "type": "github"
       }
     },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nur",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1733222881,
+        "narHash": "sha256-JIPcz1PrpXUCbaccEnrcUS8jjEb/1vJbZz5KkobyFdM=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "49717b5af6f80172275d47a418c9719a31a78b53",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
+    },
     "xwayland-satellite-stable": {
       "flake": false,
       "locked": {