[EventHorizonXT]

Related issue

Refs #2758

Problem / pressure

Two gaps in the ACP selector plumbing block any per-model configuration picker
(the Devin Fusion builder in #2758 is the first consumer):

1. Devin carries Fast Mode on a speed config select rather than a boolean
   fast-mode toggle like Codex/Claude. normalizeFastModeSelectors neither
   recognized that select as an existing Fast control nor filtered it for
   models whose declaration omits Fast, so the Fast state leaked across Devin
   models with different capabilities.
2. There was no way to ask "which config options would model X show" without
   changing the current selection. A picker that compares controls across
   models had to borrow the selected model's selectors, mixing capabilities.

Summary

• acp-selector-options.ts: treat builtin Devin's speed select as the
  per-model Fast control inside the existing normalizeFastModeSelectors
  pass — kept when the model declares fastMode, filtered when it does not,
  gated to builtin Devin only via BUILTIN_SELECT_FAST_CONFIG_IDS.
• use-acp-selector-options.ts: add useAcpModelSelectorResolver, a pure
  lookup returning the selectors, source and adapter declaration an arbitrary
  model id would get, without touching the current selection.
• use-session-acp-selector-context.ts: expose it as selectorsForModel.
• Tests: Devin speed normalization covered in
  tests/acp-selector-options.test.ts (offered → kept, not offered →
  filtered, non-Devin agents untouched).

Visual explanation

useSessionAcpSelectorContext ──► selectorOptions  (selected model, as before)
                             └─► selectorsForModel  [NEW] ──► useAcpModelSelectorResolver(modelId)
                                                                 └─► buildAcpSelectorOptions({selectedModelId: modelId})
                                                                       └─► normalizeFastModeSelectors
                                                                             └─► Devin `speed` select = Fast control (builtin only)

Before / after

Before	After
Devin speed select ignored by Fast normalization; models without declared Fast kept showing it	speed treated exactly like the Fast toggles: kept when declared, filtered when not, builtin Devin only
No per-model selector lookup; callers could only read the selected model's options	selectorsForModel(modelId) resolves any model's selectors, source and declaration without changing selection

Test plan

• pnpm --filter @lody/components exec vitest run tests/acp-selector-options.test.ts — 36 tests pass, including the new Devin speed cases.
• pnpm --filter @lody/components typecheck — clean.
• pnpm check on the full feature branch — clean; this PR is the first slice of it.

Context handoff

Original user prompt

Show original prompt

你是专门处理高复杂度软件工程任务的高级执行 Agent。

适用场景包括：
- 跨模块复杂重构
- 长链路故障排查
- 多步骤系统实现
- 常规执行 Agent 无法解决的技术问题
- 需要主模型与 Sidekick 协作的复杂任务

优先利用 Fusion 内部已有的主模型与助手分工，不进行重复设计或冗余委派。

接收边界明确的子问题后，独立完成分析、实现与测试，并向总工汇报可验证结果。

未经用户明确批准，不得自动升级到更高费用的模型或开启额外付费执行。

重要：本会话必须运行在 Devin 的 Fusion 模型（fusion-* 系列）上。如果当前会话实际未使用 Fusion，请先声明该事实并请求确认，不要用 SWE-2 冒充 Fusion。

请读取我附上的两份 Markdown 文件，按照完整开发计划书实施 Lody 的 Devin Fusion 自定义组合功能。

先完成 G0 协议能力核验，确认官方 Devin ACP 能否独立设置 Lead 和 Sidekick。确认可行后，直接在本地开发分支实现、测试并验证功能。

目标是实际可用、能向 Lody 上游提交的高质量代码，不是演示界面。请遵守仓库的 AGENTS.md 和贡献规范，优先复用现有架构。遇到上游协议阻塞时，提供真实证据及可交付的降级方案。

完成后向我汇报实际效果、测试结果、代码变更及 PR 方案。未经我批准，不要向远程仓库推送或提交 PR。

Shared conversation

Status: shared
Link: https://share.lody.ai/s/r17fb89p3ppc0qj99rkbb566z98j5ypd#access=v1.33791ff0455b99e33f50af2f1d22541dc0fa58c70b61266a0b3e3303df06f4b1