fix(flake): unpin nixpkgs-unstable to resolve broken claude-code package

Revert the nixpkgs-unstable pin to follow the branch again, as the
pinned revision shipped a broken package.

flake.lock

@@ -25,11 +25,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1772633058,
+        "lastModified": 1775077333,
-        "narHash": "sha256-SO7JapRy2HPhgmqiLbfnW1kMx5rakPMKZ9z3wtRLQjI=",
+        "narHash": "sha256-OXcxobt7lBkh1B8AjwreU+24myhtKpqeLfAeIyNLFY8=",
         "owner": "nix-community",
         "repo": "home-manager",
-        "rev": "080657a04188aca25f8a6c70a0fb2ea7e37f1865",
+        "rev": "49ca96b2714c5931e17401eff87f3edd42d2b0f2",
         "type": "github"
       },
       "original": {
@@ -76,11 +76,11 @@
     },
     "nixpkgs-unstable": {
       "locked": {
-        "lastModified": 1773597492,
+        "lastModified": 1775126147,
-        "narHash": "sha256-hQ284SkIeNaeyud+LS0WVLX+WL2rxcVZLFEaK0e03zg=",
+        "narHash": "sha256-J0dZU4atgcfo4QvM9D92uQ0Oe1eLTxBVXjJzdEMQpD0=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "a07d4ce6bee67d7c838a8a5796e75dff9caa21ef",
+        "rev": "8d8c1fa5b412c223ffa47410867813290cdedfef",
         "type": "github"
       },
       "original": {
@@ -92,11 +92,11 @@
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1772822230,
+        "lastModified": 1775002709,
-        "narHash": "sha256-yf3iYLGbGVlIthlQIk5/4/EQDZNNEmuqKZkQssMljuw=",
+        "narHash": "sha256-d3Yx83vSrN+2z/loBh4mJpyRqr9aAJqlke4TkpFmRJA=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "71caefce12ba78d84fe618cf61644dce01cf3a96",
+        "rev": "bcd464ccd2a1a7cd09aa2f8d4ffba83b761b1d0e",
         "type": "github"
       },
       "original": {