fix(agent): properly switch model when switching mode/agent

This should solves #112

Author: sudo-tee

lua/opencode/config_file.lua

@@ -85,14 +85,11 @@ function M.get_opencode_agents()
     end
   end
 
-  -- Sort the agents before prepending the default agents
   table.sort(agents)
 
-  -- Only add build/plan as fallbacks if they're not explicitly disabled in config
   for _, mode in ipairs({ 'plan', 'build' }) do
     if not vim.tbl_contains(agents, mode) then
       local mode_config = cfg.agent and cfg.agent[mode]
-      -- Only add if not explicitly disabled or if no config exists (default behavior)
       if mode_config == nil or (mode_config.disable ~= true) then
         table.insert(agents, 1, mode)
       end

lua/opencode/core.lua

@@ -312,6 +312,11 @@ function M.switch_to_mode(mode)
   end
 
   state.current_mode = mode
+  local agents_config = config_file.get_opencode_config().agent or {}
+  local mode_config = agents_config[mode] or {}
+  if mode_config.model and mode_config.model ~= '' then
+    state.current_model = mode_config.model
+  end
   return true
 end