Add copilot-api package and service

- Package copilot-api (GitHub Copilot API proxy) using bun
- Create systemd service module for copilot-api
- Enable service on ganymede listening on localhost:4141
- Add SSH port forwarding from mercury to ganymede for copilot-api
- Update gitignore to exclude Claude Code artifacts

Co-Authored-By: Claude (claude-sonnet-4.5) <noreply@anthropic.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/modules/services/nixos/copilot-api.nix b/modules/services/nixos/copilot-api.nix
new file mode 100644
index 0000000..d9d4da3
--- /dev/null
+++ b/modules/services/nixos/copilot-api.nix
@@ -0,0 +1,62 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  cfg = config.collinux.services.copilot-api;
+in {
+  config = lib.mkIf cfg.enable {
+    users.groups."copilot-api" = {};
+    users.users."copilot-api" = {
+      isSystemUser = true;
+      group = "copilot-api";
+      home = "/var/lib/copilot-api";
+      createHome = true;
+    };
+
+    systemd.services."copilot-api" = {
+      description = "GitHub Copilot API Proxy";
+      restartIfChanged = true;
+      wants = ["network-online.target"];
+      after = ["network-online.target"];
+      wantedBy = ["multi-user.target"];
+
+      serviceConfig = {
+        User = "copilot-api";
+        Group = "copilot-api";
+        Type = "simple";
+        Restart = "on-failure";
+        RestartSec = "5s";
+
+        # Load environment variables from file (e.g., GH_TOKEN)
+        EnvironmentFile = lib.mkIf (cfg.githubToken != null) cfg.githubToken;
+
+        # Security hardening
+        PrivateTmp = true;
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        ProtectKernelTunables = true;
+        ProtectControlGroups = true;
+        RestrictSUIDSGID = true;
+
+        # Allow writing to state directory
+        StateDirectory = "copilot-api";
+        WorkingDirectory = "/var/lib/copilot-api";
+
+        ExecStart = let
+          copilot-api = pkgs.callPackage ../../../pkgs/copilot-api {};
+          # Use bash to read token from environment and pass to command
+          startScript = pkgs.writeShellScript "copilot-api-start" ''
+            exec ${copilot-api}/bin/copilot-api start \
+              --port ${toString cfg.port} \
+              --host ${cfg.listenAddr} \
+              ${lib.optionalString (cfg.githubToken != null) "--github-token \"$GH_TOKEN\""}
+          '';
+        in "${startScript}";
+      };
+    };
+  };
+}