[Feat] Add Qwen3.8 Max to OpenCode Go (#1245)

* feat(opencode-go): add GLM-5.3 and Qwen3.8 Max

* chore(opencode-go): narrow model update to Qwen

* fix(opencode-go): avoid unsupported reasoning preservation

* chore(opencode-go): keep provider sections separated

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Co-authored-by: @taltas <6816042+taltas@users.noreply.github.com>