feat(agents/opencode): add synthetic/ model prefix

Amolith created 

Assisted-by: Claude Sonnet 4.5 via Crush

Change summary

functions/_synu_agents/opencode.fish | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Detailed changes

functions/_synu_agents/opencode.fish 🔗 

@@ -40,9 +40,9 @@ function _synu_agent_opencode_configure --description "Configure OpenCode model
 end
 
 function _synu_agent_opencode_args --description "Return CLI arguments to pass to opencode"
-    # Return -m flag with selected model
+    # Return -m flag with selected model, prefixed with synthetic/ for provider routing
     echo -m
-    echo $_synu_opencode_selected_model
+    echo "synthetic/$_synu_opencode_selected_model"
 end
 
 function _synu_agent_opencode_interactive --description "Interactive model selection using gum"