flake.lock: Update

Flake lock file updates:

```
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/78add7b7abb61689e34fc23070a8f55e1d26185b' (2025-05-28)
  → 'github:nixos/nixpkgs/d883b6213afa179b58ba8bace834f1419707d0ad' (2025-06-19)
• Updated input 'nixpkgs-unstable':
    'github:nixos/nixpkgs/910796cabe436259a29a72e8d3f5e180fc6dfacc' (2025-05-31)
  → 'github:nixos/nixpkgs/08f22084e6085d19bcfb4be30d1ca76ecb96fe54' (2025-06-19)
• 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": 1749668643,
+        "lastModified": 1750330365,
-        "narHash": "sha256-gaWJEWGBW/g1u6o5IM4Un0vluv86cigLuBnjsKILffc=",
+        "narHash": "sha256-hJ7XMNVsTnnbV2NPmStCC07gvv5l2x7+Skb7hyUzazg=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "1965fd20a39c8e441746bee66d550af78f0c0a7b",
+        "rev": "d883b6213afa179b58ba8bace834f1419707d0ad",
         "type": "github"
       },
       "original": {
@@ -36,11 +36,11 @@
     },
     "nixpkgs-unstable": {
       "locked": {
-        "lastModified": 1749794982,
+        "lastModified": 1750365781,
-        "narHash": "sha256-Kh9K4taXbVuaLC0IL+9HcfvxsSUx8dPB5s5weJcc9pc=",
+        "narHash": "sha256-XE/lFNhz5lsriMm/yjXkvSZz5DfvKJLUjsS6pP8EC50=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "ee930f9755f58096ac6e8ca94a1887e0534e2d81",
+        "rev": "08f22084e6085d19bcfb4be30d1ca76ecb96fe54",
         "type": "github"
       },
       "original": {