Update opencode.nix: use OpenRouter model IDs, add Nitro routing, set compact agent mode to primary

home/modules/opencode.nix

@@ -3,11 +3,33 @@
 {
   xdg.configFile."opencode/opencode.json".text = builtins.toJSON {
     "$schema" = "https://opencode.ai/config.json";
+    provider = {
+      openrouter = {
+        models = {
+          "openrouter/openai/gpt-oss-120b" = {
+            options = {
+              provider = {
+                order = [ "Nitro" ];
+                allow_fallbacks = true;
+              };
+            };
+          };
+          "openrouter/moonshotai/kimi-k2.5" = {
+            options = {
+              provider = {
+                order = [ "Nitro" ];
+                allow_fallbacks = true;
+              };
+            };
+          };
+        };
+      };
+    };
     agent = {
       commit = {
         description = "Creates a one-line git commit describing the changes";
-        mode = "subagent";
-        model = "openai/gpt-oss-120b:nitro";
+        mode = "primary";
+        model = "openrouter/openai/gpt-oss-120b";
         prompt = ''
           You are a git commit agent. When invoked:
           1. Run `git status` and `git diff` to understand all changes
@@ -25,8 +47,8 @@
       };
       compact = {
         description = "Compacts and summarizes conversation context to reduce token usage";
-        mode = "subagent";
-        model = "moonshotai/kimi-k2.5:nitro";
+        mode = "primary";
+        model = "openrouter/openai/gpt-oss-120b";
         prompt = ''
           You are a context compaction specialist. Your job is to summarize and compress the conversation history while preserving:
           1. Key decisions and their rationale