chore(deps): update flake.lock (#3250)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/e9a7635' (2026-05-29)
  → 'github:NixOS/nixpkgs/cbb5cf3' (2026-06-06)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/85570ef' (2026-05-30)
  → 'github:oxalica/rust-overlay/27b7e78' (2026-06-06)

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1780030872,
-        "narHash": "sha256-u6WU/yd/o8iYQrHX3RAwO1hYa3LkoSL+WNQD0rJfJZQ=",
+        "lastModified": 1780747962,
+        "narHash": "sha256-IX7G1dlKrOqPOImfbo7ADDfV5yU1+j+MRChI3TL4tAA=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "e9a7635a57597d9754eccebdfc7045e6c8600e6b",
+        "rev": "cbb5cf358f50aa6acc9efd6113b7bcfbc352cd73",
         "type": "github"
       },
       "original": {
@@ -29,11 +29,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1780110990,
-        "narHash": "sha256-6QBThUi7SuK+dgA+DCaEkQGZN4kYx6DpXmK45+MG9zI=",
+        "lastModified": 1780715792,
+        "narHash": "sha256-4+8gPeiPeud89mjo865RwpqmKwa1MThRsq2SvRxo7mg=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "85570ef134d92a8702de6afd1f6f0209c863fa91",
+        "rev": "27b7e78c6935293ee868469cc4172e9b8b17823b",
         "type": "github"
       },
       "original": {