spicedb: add shell completion

This commit adds shell completion for bash, fish, and zsh to both
spicedb and zed, leveraging their `completion` subcommands with bash
process substitution.

Signed-off-by: squat <lserven@gmail.com>

pkgs/servers/spicedb/default.nix

@@ -2,6 +2,7 @@
   lib,
   buildGoModule,
   fetchFromGitHub,
+  installShellFiles,
 }:
 
 buildGoModule rec {
@@ -23,6 +24,15 @@ buildGoModule rec {
 
   subPackages = [ "cmd/spicedb" ];
 
+  nativeBuildInputs = [ installShellFiles ];
+
+  postInstall = ''
+    installShellCompletion --cmd spicedb \
+      --bash <($out/bin/spicedb completion bash) \
+      --fish <($out/bin/spicedb completion fish) \
+      --zsh <($out/bin/spicedb completion zsh)
+  '';
+
   meta = with lib; {
     description = "Open source permission database";
     longDescription = ''

pkgs/servers/spicedb/zed.nix

@@ -2,6 +2,7 @@
   lib,
   buildGoModule,
   fetchFromGitHub,
+  installShellFiles,
 }:
 
 buildGoModule rec {
@@ -21,6 +22,15 @@ buildGoModule rec {
     "-X 'github.com/jzelinskie/cobrautil/v2.Version=${src.rev}'"
   ];
 
+  nativeBuildInputs = [ installShellFiles ];
+
+  postInstall = ''
+    installShellCompletion --cmd zed \
+      --bash <($out/bin/zed completion bash) \
+      --fish <($out/bin/zed completion fish) \
+      --zsh <($out/bin/zed completion zsh)
+  '';
+
   meta = with lib; {
     description = "Command line for managing SpiceDB";
     mainProgram = "zed";