feat(lsp): LSP capability seam, generic stdio provider, and lsp tool

Implements the LSP capability seam RFC as three packages: dsh-lsp (the
ctx.lsp interface — provider registry by branded id + exclusive extension
mapping, per-query order-independent selection, closed request/result
vocabulary, LspError taxonomy), dsh-lsp-local (a generic stdio language-server
provider — Content-Length JSON-RPC framing, per-(provider, workspace) process
single-flight, transient didOpen/query/didClose, an abortable per-instance
queue, UTF-16 negotiation, host-namespace source reads outside ctx.fs, and
bounded shutdown/kill teardown), and dsh-tool-lsp (the model-facing lsp tool —
four operations, one-based UTF-16 cursor conversion, workspace-grouped location
rendering, hover capping, a required session workspace, and a timeout budget).

Why: an agent had text search and file reads but no way to identify a program
symbol — follow an alias, connect an interface to implementations, or read an
inferred type — before changing code. Splitting model contract, seam, and local
subprocess behavior keeps the four semantic queries stable across future remote
or sandbox-native providers without leaking a JSON-RPC escape hatch.

docs/rfc/INDEX.md

@@ -28,7 +28,6 @@ Generated by `pnpm run gen-rfc-index` from the RFC tree — never edit by hand;
 |---|---|
 | [Runtime schemas for the event vocabulary (Zod vs the merge-extensible-map pattern)](proposed/architecture/2026-06-16-typed-event-schemas.md) | 2026-06-16 |
 | [Extract a generic long-running tool runtime](proposed/architecture/2026-06-20-generic-long-running-tool-runtime.md) | 2026-06-20 |
-| [LSP capability seam and model-facing query tool](proposed/architecture/2026-07-15-lsp-capability-seam.md) | 2026-07-15 |
 
 ### Process
 
@@ -146,6 +145,7 @@ Generated by `pnpm run gen-rfc-index` from the RFC tree — never edit by hand;
 | [The agent is a registration scope](implemented/architecture/2026-07-08-agent-scope-contexts.md) | 2026-07-08 |
 | [Single-file executable SDK runtime distribution (single-exe)](implemented/architecture/2026-07-10-single-file-executable-sdk-runtime-distribution.md) | 2026-07-10 |
 | [Agent-scope runtime design and correctness](implemented/architecture/2026-07-12-agent-scope-runtime-design.md) | 2026-07-12 |
+| [LSP capability seam and model-facing query tool](implemented/architecture/2026-07-15-lsp-capability-seam.md) | 2026-07-15 |
 
 ### Process
 

docs/rfc/implemented/architecture/2026-07-15-lsp-capability-seam.i18n.yaml

@@ -2,5 +2,5 @@
 # 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
-2026-07-15-lsp-capability-seam.md: 89e58c3ae0ba9f49ed0164a76a230b141296eee5
-2026-07-15-lsp-capability-seam.zh.md: c1c2448b1e980fc17a347f6c434e8553639304f3
+2026-07-15-lsp-capability-seam.md: 90cc7fce8ce86582cc27bd70fadcc46309438983
+2026-07-15-lsp-capability-seam.zh.md: 12873d33684255b7177a78dd4588e11aa61eb26b

docs/rfc/implemented/architecture/2026-07-15-lsp-capability-seam.md

@@ -1,6 +1,6 @@
 # RFC: LSP capability seam and model-facing query tool
 
-Status: proposed
+Status: implemented
 
 English | [中文](2026-07-15-lsp-capability-seam.zh.md)
 
@@ -12,7 +12,7 @@ LSP support has three owners: the model needs a stable query schema, the harness
 
 Many language servers behave best when the queried document is opened with current text. A compatible agent client must bound that state, define whether its source read is a model observation, and keep the document snapshot in the same filesystem namespace as the server's workspace index.
 
-## Proposal
+## Decision
 
 Add LSP as a three-package capability seam with one read-only model tool and one generic local provider implementation:
 
@@ -171,7 +171,7 @@ The local provider trusts its configured server and claims no sandbox confinemen
 
 **Ship presets or PATH discovery.** A catalog would make the generic host own language policy, while discovery cannot infer arguments, language ids, or initialization. Deployments configure providers explicitly; composition plugins may package presets.
 
-## Acceptance criteria
+## Testing
 
 - Package tests pin the three-package dependency direction, runtime injections, and `ctx.lsp`-only communication.
 - Tool tests pin the four operations, coordinate validation, configured bounds and omission markers, prompt, and ACP presentation.
@@ -185,7 +185,7 @@ The local provider trusts its configured server and claims no sandbox confinemen
 - Snapshots cover model-visible schema, prompt, results, omissions, and ACP rendering; a built-artifact smoke test covers framing and cleanup.
 - Package and architecture docs cover configuration, security boundaries, and search/read guidance; the new `packages/lsp/` group is added to the AGENTS.md repository-layout block, the packages/README.md group table, and architecture.md in the same change.
 
-## Risks
+## Consequences
 
 Language servers vary in method support, capability interpretation, and indexing readiness; LSP has no universal “index complete” signal. Servers without compatible transient-open synchronization are unsupported even if closed-document queries work. Supported servers may still return empty or partial results, so the tool promises no cross-server completeness. The pinned TypeScript e2e establishes one compatibility floor, not a cross-language claim.
 

docs/rfc/implemented/architecture/2026-07-15-lsp-capability-seam.zh.md

@@ -1,6 +1,6 @@
 # RFC: LSP 能力服务边界与面向模型的查询工具
 
-Status: proposed
+Status: implemented
 
 [English](2026-07-15-lsp-capability-seam.md) | 中文
 
@@ -12,7 +12,7 @@ harness 已具备文本搜索与文件读取能力，但二者都无法识别程
 
 许多语言服务器只有在查询文档已按当前文本打开时才能稳定工作。兼容的 agent 客户端必须限制这项状态、定义内部读取是否算作模型观察，并确保文档快照与服务器工作区索引位于同一文件系统命名空间。
 
-## 提案
+## 决策
 
 将 LSP 建成由三个 package 组成的能力服务边界，其中包含一个只读模型工具和一个通用本地提供方实现：
 
@@ -171,7 +171,7 @@ ACP 使用 `{ card: 'generic', kind: 'search', title, locations: [{ path: file_p
 
 **内置 preset 或 PATH 发现。** 目录会让通用 host 承担语言策略，而发现机制无法推断参数、语言 id 或初始化配置。部署显式配置提供方，组合插件可以封装 preset。
 
-## 验收标准
+## 测试
 
 - Package 测试固定三个 package 的依赖方向、运行时注入和仅通过 `ctx.lsp` 通信的边界。
 - 工具测试固定四种操作、坐标校验、配置限制与省略标记、提示词和 ACP 展示。
@@ -185,7 +185,7 @@ ACP 使用 `{ card: 'generic', kind: 'search', title, locations: [{ path: file_p
 - 快照覆盖模型可见 schema、提示词、结果、省略提示和 ACP 渲染；构建产物冒烟测试覆盖分帧与清理。
 - Package 与架构文档覆盖配置、安全边界和搜索/读取指导；同一改动中，新的 `packages/lsp/` package 组要加入 AGENTS.md 的仓库布局块、packages/README.md 的分组表和 architecture.md。
 
-## 风险
+## 影响
 
 各语言服务器对方法支持、能力解释和索引就绪时机的处理不同；LSP 没有统一的“索引完成”信号。无法声明兼容临时打开同步能力的服务器不受支持，即使它能查询已关闭文档。受支持的服务器仍可能返回空结果或不完整结果，因此工具不承诺跨服务器完整性。固定的 TypeScript e2e 只建立一条兼容性基线，不代表跨语言承诺。