feat(agent): implement model tier selection with variant support for subagents#11377

mcking-07 wants to merge 2 commits intoanomalyco:devanomalyco/opencode:devfrom

mcking-07:feature/subagent-model-and-variant-selection-via-model-tiersmcking-07/opencode:feature/subagent-model-and-variant-selection-via-model-tiersCopy head branch name to clipboard