flake.lock: Update

Flake lock file updates:

```
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/78add7b7abb61689e34fc23070a8f55e1d26185b' (2025-05-28)
  → 'github:nixos/nixpkgs/1965fd20a39c8e441746bee66d550af78f0c0a7b' (2025-06-11)
• Updated input 'nixpkgs-unstable':
    'github:nixos/nixpkgs/910796cabe436259a29a72e8d3f5e180fc6dfacc' (2025-05-31)
  → 'github:nixos/nixpkgs/ee930f9755f58096ac6e8ca94a1887e0534e2d81' (2025-06-13)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/1f3f7b784643d488ba4bf315638b2b0a4c5fb007' (2025-05-26)
  → 'github:numtide/treefmt-nix/a05be418a1af1198ca0f63facb13c985db4cb3c5' (2025-06-06)
```

flake.lock

@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1749173751,
+        "lastModified": 1749668643,
-        "narHash": "sha256-ENY3y3v6S9ZmLDDLI3LUT8MXmfXg/fSt2eA4GCnMVCE=",
+        "narHash": "sha256-gaWJEWGBW/g1u6o5IM4Un0vluv86cigLuBnjsKILffc=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "ed29f002b6d6e5e7e32590deb065c34a31dc3e91",
+        "rev": "1965fd20a39c8e441746bee66d550af78f0c0a7b",
         "type": "github"
       },
       "original": {
@@ -36,11 +36,11 @@
     },
     "nixpkgs-unstable": {
       "locked": {
-        "lastModified": 1749285348,
+        "lastModified": 1749794982,
-        "narHash": "sha256-frdhQvPbmDYaScPFiCnfdh3B/Vh81Uuoo0w5TkWmmjU=",
+        "narHash": "sha256-Kh9K4taXbVuaLC0IL+9HcfvxsSUx8dPB5s5weJcc9pc=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "3e3afe5174c561dee0df6f2c2b2236990146329f",
+        "rev": "ee930f9755f58096ac6e8ca94a1887e0534e2d81",
         "type": "github"
       },
       "original": {