fix(git-identity): use existing gitea SSH key for agent commits

The m3ta-chiron SSH key was not accepted by Gitea.
Using the existing gitea key instead for push authentication.

home/coding/agents/agents.nix

@@ -10,11 +10,12 @@
   ...
 }: {
   # Agent Git Identity configuration
+  # Note: Uses existing gitea SSH key (m3tam3re identity) for push auth
   coding.agents.gitIdentity = {
     enable = true;
     name = "m3ta-chiron";
     email = "m3ta-chiron@agentmail.to";
-    sshKey = "/home/m3tam3re/.ssh/m3ta-chiron";
+    sshKey = "/home/m3tam3re/.ssh/gitea";
   };
 
   imports = [