fix: resolve Gitea Actions authentication issue in nix-update workflow

- Replace actions/checkout@v4 with manual git clone using token-embedded
  URL to fix 'could not read Username: terminal prompts disabled' error
- Disable GIT_TERMINAL_PROMPT and GIT_ASKPASS to prevent interactive prompts
- Consolidate git config setup into checkout step

Package updates:
- beads: 0.47.1 -> 0.47.2
- opencode: 1.1.18 -> 1.1.25

Beads state sync:
- Close nixpkgs-8jw (Gitea Actions node PATH issue resolved)
- Close nixpkgs-r3u (Gitea Actions nix-update workflow complete)
- Create nixpkgs-8ng (opencode subpackage update requires special args)
- Remove deleted tombstone issues

pkgs/beads/default.nix

@@ -10,16 +10,16 @@
 }:
 buildGoModule (finalAttrs: {
   pname = "beads";
-  version = "0.47.1";
+  version = "0.47.2";
 
   src = fetchFromGitHub {
     owner = "steveyegge";
     repo = "beads";
     tag = "v${finalAttrs.version}";
-    hash = "sha256-DwIR/r1TJnpVd/CT1E2OTkAjU7k9/KHbcVwg5zziFVg=";
+    hash = "sha256-yj57dWrxNO8hp1q/W3VX9bQbvJZhUdLpvDqhfwJM7UA=";
   };
 
-  vendorHash = "sha256-pY5m5ODRgqghyELRwwxOr+xlW41gtJWLXaW53GlLaFw=";
+  vendorHash = "sha256-YU+bRLVlWtHzJ1QPzcKJ70f+ynp8lMoIeFlm+29BNPE=";
 
   subPackages = ["cmd/bd"];