update opencode config, secrets, tailscale, and agents input

- opencode: remove deprecated google_auth, add git_master config,
  experimental truncation, use glm-4.6v for multimodal-looker,
  upgrade categories to glm-5, remove opencode-memory plugin
- m3-atlas: add ref/exa/outline/basecamp secret declarations
- m3-kratos: enable tailscale with ssh and reset flags
- agents: switch back to remote git input

hosts/m3-kratos/services/tailscale.nix

@@ -1,12 +1,13 @@
 {config, ...}: {
   services.tailscale = {
-    enable = false;
+    enable = true;
     authKeyFile = config.age.secrets.tailscale-key.path;
     useRoutingFeatures = "both";
     extraUpFlags = [
       "--login-server=https://va.m3tam3re.com"
       "--accept-routes"
-      "--exit-node-allow-lan-access"
+      "--ssh"
+      "--reset"
     ];
   };
 }