feat(pkgs): add bv-bin v0.13.0 beads viewer package

- Add cross-platform binary package (linux/darwin, x86_64/aarch64)
- Graph-aware task management TUI for beads projects
- MIT licensed, sources from GitHub releases

Author: DivitMittal

pkgs/custom/bv-bin/package.nix

@@ -0,0 +1,60 @@
+{
+  lib,
+  stdenvNoCC,
+  fetchurl,
+  ...
+}: let
+  version = "0.13.0";
+  pname = "bv";
+
+  sources = {
+    "x86_64-linux" = {
+      url = "https://github.com/Dicklesworthstone/beads_viewer/releases/download/v${version}/bv_${version}_linux_amd64.tar.gz";
+      hash = "sha256-8Ux9Brf2u78ljmTB49EBXCAn41WssOl8c+dZ1DZDjkw=";
+    };
+    "aarch64-linux" = {
+      url = "https://github.com/Dicklesworthstone/beads_viewer/releases/download/v${version}/bv_${version}_linux_arm64.tar.gz";
+      hash = "sha256-dxkewC884pA0exBZFixC2A+VgTw5ZyirnD8Zj9ncAwg=";
+    };
+    "x86_64-darwin" = {
+      url = "https://github.com/Dicklesworthstone/beads_viewer/releases/download/v${version}/bv_${version}_darwin_amd64.tar.gz";
+      hash = "sha256-n7+K0grNaNKDvrJurt25Ow3/2wuWVvrjp38fFWcPYfA=";
+    };
+    "aarch64-darwin" = {
+      url = "https://github.com/Dicklesworthstone/beads_viewer/releases/download/v${version}/bv_${version}_darwin_arm64.tar.gz";
+      hash = "sha256-eCA/NKQ7QT9KEEOtBiwOb9ksxj2k202ENK1tWKOdCEY=";
+    };
+  };
+
+  platformSource = sources.${stdenvNoCC.hostPlatform.system} or (throw "Unsupported platform: ${stdenvNoCC.hostPlatform.system}");
+in
+  stdenvNoCC.mkDerivation {
+    inherit pname version;
+
+    src = fetchurl {
+      inherit (platformSource) url hash;
+    };
+
+    sourceRoot = ".";
+
+    dontConfigure = true;
+    dontBuild = true;
+
+    installPhase = ''
+      runHook preInstall
+
+      install -Dm755 bv $out/bin/bv
+
+      runHook postInstall
+    '';
+
+    meta = {
+      description = "Graph-aware task management TUI for beads projects";
+      homepage = "https://github.com/Dicklesworthstone/beads_viewer";
+      license = lib.licenses.mit;
+      platforms = lib.attrNames sources;
+      maintainers = with lib.maintainers; [DivitMittal];
+      sourceProvenance = with lib.sourceTypes; [binaryNativeCode];
+      mainProgram = "bv";
+    };
+  }