refactor(credentials,llm): remove speculative mutation and route lifecycle

.agents/notes/implemented/simplification/2026-07-31-read-only-credentials-and-static-llm-routes.i18n.yaml

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+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write .agents/notes/implemented/simplification/2026-07-31-read-only-credentials-and-static-llm-routes.md
+2026-07-31-read-only-credentials-and-static-llm-routes.md: 2ebbea28c2dadeb9482c483247249ed4054749e4
+2026-07-31-read-only-credentials-and-static-llm-routes.zh.md: ad21d93bf73ca0063eb97da8e610aa2814ee1726

.agents/notes/implemented/simplification/2026-07-31-read-only-credentials-and-static-llm-routes.md

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+# Agent Note: read-only credentials and static LLM routes
+
+Status: implemented
+
+English | [中文](2026-07-31-read-only-credentials-and-static-llm-routes.zh.md)
+
+## Problem
+
+The first request-level LLM configuration design shipped future configuration-UI capabilities before that UI existed. The credential seam exposed description, mutation, and change events; its local provider therefore needed a watcher, cache, operation queue, dotenv editor, writer lock, and a new shared atomic-write package. No production caller used those operations. Mutable adapter registrations and a dormant pi-ai mount similarly existed so settings could create routes even though provider ownership is a composition decision.
+
+That speculative closure accounted for much of the feature's runtime and test growth, widened public contracts, and introduced lifecycle and concurrency failure modes unrelated to the two current consumers, which only need to resolve a named key for a request.
+
+## Decision
+
+`ctx.credentials` exposes only branded `CredentialRef` construction and `resolve(ref): Promise<string | undefined>`. `credentials-local` reads the named process environment value, then parses its dotenv file on demand. It owns no mutation, description, event, watcher, cache, editor, or writer lifecycle; externally changing either source is visible to the next resolution.
+
+LLM provider routes and their retry policies are composition-owned. `registerAdapter()` returns a disposer rather than a mutable registration handle. DeepSeek always owns its one route, and pi-ai requires a non-empty configured route map; settings may change request-level facts for those existing routes but cannot create, remove, or retune registrations. The shared CLI composition therefore does not mount an empty pi-ai adapter.
+
+The optional-settings helper only switches a consumer's source thunk between its composition entry and a live settings scope. Consumers read committed values through that thunk, so the helper needs no update watcher, derived-state callback, or teardown-state mirror. `settings-local` keeps its write protocol private instead of publishing a utility for a second writer that no longer exists.
+
+## Alternatives considered
+
+**Keep the credential writer for the planned web surface.** A future UI may need mutation and redacted description, but its exact RPC, ownership, and security contract is not shipped. Reintroducing the smallest closure with that consumer is cheaper than maintaining a generic write lifecycle meanwhile.
+
+**Cache the dotenv file and watch for invalidation.** Per-resolution file I/O is small beside a model request and makes external rotation current without watcher readiness, debounce, missed-event, and disposal semantics.
+
+**Keep mutable route registration as a generic registry feature.** Current adapters know their provider routes at composition. A mutable public handle creates a lifecycle state solely for a deferred settings-driven route feature.
+
+**Keep a shared atomic-write package for settings alone.** One consumer does not justify a public package, peer dependency, invariant companion, and independent test surface; the settings provider owns its private write protocol.
+
+## Consequences
+
+Credential rotation remains restart-free when an operator or external secret manager changes the environment or dotenv document, but the harness offers no credential-management API or UI contract. pi-ai deployments explicitly compose at least one provider route. The remaining public seams match current production calls, and the removed watcher/editor/registration machinery no longer contributes concurrency or teardown states.
+
+Focused seam, provider, dynamic-settings, Loader-composition, and missing-credential snapshot tests pin the smaller closure. The earlier [request-level configuration](../architecture/2026-07-29-request-level-llm-config-credentials.md) and [credential-boundary](../architecture/2026-07-30-credential-boundaries-and-atomic-registration.md) notes retain the motivation and surviving request/security decisions while deferring to this note for the removed mutation and route-lifecycle contracts.

.agents/notes/implemented/simplification/2026-07-31-read-only-credentials-and-static-llm-routes.zh.md

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+# Agent Note（agent 决策记录）：只读凭据与静态 LLM（大语言模型）路由
+
+Status: implemented
+
+[English](2026-07-31-read-only-credentials-and-static-llm-routes.md) | 中文
+
+## 问题
+
+第一版请求级 LLM 配置设计在相应 UI 尚不存在时，便交付了面向未来配置 UI 的能力。凭据 seam 暴露描述、修改和变更事件，因此本地提供方需要 watcher、缓存、操作队列、dotenv 编辑器、写入锁，以及一个新的共享 atomic-write 包（package）。没有生产调用方使用这些操作。可变适配器注册与休眠的 pi-ai 挂载同样是为了让 settings 创建路由而存在，尽管提供方所有权属于组合决策。
+
+这些超前加入的能力占据了该功能大部分运行时与测试增量，扩大了公开契约，还引入了与两个当前消费方无关的生命周期和并发失败模式；这两个消费方只需要为一次请求解析点名的密钥。
+
+## 决策
+
+`ctx.credentials` 只暴露品牌化 `CredentialRef` 的构造，以及 `resolve(ref): Promise<string | undefined>`。`credentials-local` 先读取点名的进程环境值，再按需解析其 dotenv 文件。它不拥有修改、描述、事件、watcher、缓存、编辑器或写入器生命周期；从外部更改任一来源，都会在下一次解析时生效。
+
+LLM 提供方路由及其重试策略归组合所有。`registerAdapter()` 返回释放器，而非可变注册句柄。DeepSeek 始终拥有自身唯一的路由，pi-ai 则要求配置一份非空路由映射；settings 可以更改这些现有路由的请求级事实，但不能创建、移除或重新调整注册。因此，共享 CLI（命令行界面）组合不会挂载空的 pi-ai 适配器。
+
+可选 settings 辅助工具只在组合配置项与存活 settings scope 之间切换消费方的来源 thunk。消费方经该 thunk 读取已提交值，因此辅助工具不需要更新 watcher、派生状态回调或拆卸状态镜像。`settings-local` 将自身的写入协议保留为私有实现，不再为一个已不存在的第二写入方公开工具。
+
+## 曾考虑的替代方案
+
+**为计划中的 web surface 保留凭据写入器。**未来的 UI 可能需要变更与脱敏后的描述，但其确切 RPC、所有权和安全契约尚未交付。届时随消费方重新引入满足需求的最小能力闭包，比在此期间维护通用写入生命周期成本更低。
+
+**缓存 dotenv 文件并通过 watcher 触发失效。**相比一次模型请求，每次解析执行的文件 I/O 很小；直接读取可以让外部轮换始终生效，而无需引入 watcher 就绪、防抖、事件漏失与资源释放语义。
+
+**保留可变路由注册，将其作为通用注册表功能。**当前适配器在组合时便已知自身的提供方路由。可变公开句柄只为一项延后的 settings 驱动路由功能创建了生命周期状态。
+
+**只为 settings 保留共享 atomic-write 包。**一个消费方不足以证明公开包、对等依赖（peer dependency）、不变量配套实现与独立测试面的必要性；settings 提供方拥有自身的私有写入协议。
+
+## 后果
+
+当操作者或外部机密管理器更改环境或 dotenv 文档时，凭据轮换仍然无需重启，但 harness 不提供凭据管理 API 或 UI 契约。pi-ai 部署必须显式组合至少一条提供方路由。余下公开 seam 与当前生产调用相符，被移除的 watcher、编辑器与注册机制也不再引入并发或拆卸状态。
+
+针对 seam、提供方、动态 settings、Loader 组合与凭据缺失快照的聚焦测试固定了这个更小的能力闭包。先前的[请求级配置](../architecture/2026-07-29-request-level-llm-config-credentials.md)与[凭据边界](../architecture/2026-07-30-credential-boundaries-and-atomic-registration.md) note 保留其动机以及仍然适用的请求与安全决策；对于已移除的变更和路由生命周期契约，则以本 note 为准。