docs: shorten Overriding nixpkgs section

README.md

@@ -92,22 +92,13 @@ whitelist to itself, nothing for the operator to set.
 
 ### Overriding nixpkgs
 
-hyperhive's own `flake.nix` pins `nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05"`
-so the repo builds standalone (`nix flake check`, CI, `nix develop`) without
-depending on a consumer's host flake. When you import hyperhive as a flake
-input into your own host config, that pin becomes a second nixpkgs
-evaluation living alongside your host's — extra closure to build/cache, and
-a second place package versions can drift from what the rest of your system
-runs.
-
-Add `hyperhive.inputs.nixpkgs.follows = "nixpkgs"` to your input declaration
-(as in the quick-start above) to make hyperhive build against your host's
-`nixpkgs` input instead of its own pinned one. This is the standard flake
-`follows` pattern — nothing hyperhive-specific — and works as long as your
-`nixpkgs` is reasonably close to the `nixos-26.05` release hyperhive is
-developed against; a much older or newer channel may hit `nixpkgs`-side
-breakage hyperhive's CI doesn't catch. If you hit that, drop the `follows`
-line and let hyperhive use its own pin again.
+hyperhive pins its own `nixpkgs` so it builds standalone in CI. Add
+`hyperhive.inputs.nixpkgs.follows = "nixpkgs"` (as in the quick-start above)
+to build it against your host's `nixpkgs` instead — one less nixpkgs
+evaluation, no version drift from the rest of your system. Standard flake
+`follows` pattern; works as long as your channel is reasonably close to the
+`nixos-26.05` hyperhive develops against. Drop it again if a much
+older/newer channel hits breakage hyperhive's CI doesn't catch.
 
 For the full list of host and agent NixOS options see the
 **[options reference](https://hyperhive.darkest.space/options/)**.