build(deps): update flake.lock (#5544)

* flake.lock: Update

Flake lock file updates:

• Updated input 'devenv':
    'github:cachix/devenv/ef185b5a38445777194bc8469fc1cdebd99e7dbc?narHash=sha256-EeZH7UbjqoJHHrN1DkV32DxZ8OMGh/2kla94lpO17eE%3D' (2026-07-22)
  → 'github:cachix/devenv/60b80be9e10ea07ff79c44a39741a75afd74f6a9?narHash=sha256-wY6Lll/lmIh2icBNoviibNwdrbhUQwdS7J92VIvdAxw%3D' (2026-07-25)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/fd1462031fdee08f65fd0b4c6b64e22239a77870?narHash=sha256-n3gKTBIV4ZA5VQpUakffBe3KGu4%2BmhPoA34rrqS0GkA%3D' (2026-07-19)
  → 'github:NixOS/nixpkgs/b3fe9581c9061c749abef42b6d4ee7b7c05c33fa?narHash=sha256-2V/6imsUgB7mPZlHY54oeVBRDoZbPKnvzwkAHUSSufk%3D' (2026-07-22)

* docs: update changelog

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Jakob Lichterfeld <jakob-lichterfeld@gmx.de>

Author: github-actions[bot]

CHANGELOG.md

@@ -68,6 +68,7 @@
 - build(deps): bump immutable from 5.1.5 to 5.1.9 in /assets (#5541)
 - ci(treefmt): stop treefmt.toml from drifting out of sync with the flake (#5545 - @JakobLichterfeld)
 - style(nix): format Nix code with nixfmt instead of the archived nixpkgs-fmt (#5545 - @JakobLichterfeld)
+- build(deps): update flake.lock (#5544)
 
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