Enhance connection diagnostics to not only check connectivity but also verify functional compatibility of providers, detecting issues where endpoints are reachable but functionally incompatible (e.g., specific features or roles are not supported).
# [Feature]: 升级连接诊断为 capability-aware / Improve connection diagnostics with capability-aware detection ## Problem / pain point / 问题 当前连接测试已经比“只测 `/models`”更强,但仍然会遇到“技术上能连通,功能上不兼容”的情况: - `/models` 不存在,但 inference 实际可用 - `chat/completions` 可用,但 `responses` 不可用 - gateway 拒绝 `developer` role - auth 正常,但 selected wire 不兼容 Current tests are already better than a naive `/models` probe, but users can still hit endpoints that are reachable while functionally incompatible. ## Proposed solution / 方案 把 diagnostics 从“能不能连上”升级成“哪一层不兼容”。 Classify failures across: - authentication / 鉴权 - endpoint shape / endpoint 形状 - wire support / wire 兼容性 - model discovery / 模型发现 - role compatibility / role 兼容 - reasoning compatibility / reasoning 兼容 Where possible, return structured results that can also feed capability updates or UI hints. ## Alternatives considered / 备选方案 - 维持简单 pass/fail - 对 multi-gateway 场景信息不足 ## Scope / 范围 Provider / model ## Acceptance criteria / 验收标准 - diagnostics 区分 auth、