Add host-configurable LSP server

doc/manual/souce/components.md

@@ -43,14 +43,20 @@ The WebAssembly package is for execution, not syntax highlighting.
 
 Semantic editor integration lives in the host-configurable language service crate.
 It depends only on the runtime and accepts the same `HostEnvironment` implementation used by a production application.
-A host-specific LSP binary can link this crate with its loader and global schema configuration without reimplementing evaluation rules.
+The LSP crate adapts that service to the Language Server Protocol over stdin/stdout.
+It provides full document synchronization, semantic diagnostics, and whole-document formatting.
+A host-specific LSP binary injects its loader and global schema configuration without reimplementing evaluation rules.
 
 Important paths:
 
 ```text
 crates/decodal-language-service/
+crates/decodal-lsp/
 ```
 
+The default `decodal-lsp` binary reads Decodal imports from the filesystem.
+Embedded hosts can call its library entry point with a custom `LspEnvironment` to reuse structured imports and to make unsaved external documents, such as Markdown, visible to the loader.
+
 Source formatting lives in a separate Rust language tools crate.
 Keeping it separate prevents host-specific semantic services from inheriting the formatter's Tree-sitter and WebAssembly dependencies.
 
@@ -124,6 +130,7 @@ Consumers that need syntax information should use the component that matches the
 - Browser execution: `decodal-wasm`
 - Web formatting and editor syntax: Lezer / CodeMirror
 - Semantic editor analysis: `decodal-language-service`
+- Language Server Protocol integration: `decodal-lsp`
 - Rust formatting: `decodal-language-tools`
 - General editor syntax: Tree-sitter
 

doc/manual/souce/design/embedding-api.md

@@ -182,6 +182,24 @@ let analysis = service.analyze("site.dcdl", "site.dcdl", source);
 Each analysis uses a fresh engine and runs the normal parse, evaluate, and materialize pipeline.
 An environment may create loaders backed by shared filesystem, database, or editor-overlay state when repeated analysis needs a current workspace snapshot.
 
+The LSP adapter constructs that environment after receiving the client's initialization parameters:
+
+```rust
+use decodal_lsp::{LspEnvironment, run_stdio};
+
+impl LspEnvironment for AppEnvironment {}
+
+run_stdio(|initialize| {
+    let _ = initialize;
+    Ok(AppEnvironment)
+})?;
+```
+
+`LspEnvironment` adds document lifecycle hooks on top of `HostEnvironment`.
+A `run_stdio` environment factory always receives the client's `InitializeParams`; the host decides whether to use its workspace folders, initialization options, and capabilities or ignore them.
+A host that keeps unsaved buffers in shared state can update them from `open_document`, `change_document`, and `close_document`; every subsequent diagnostic pass creates the normal import loader from that updated environment.
+Synchronized non-Decodal documents are passed through these hooks but are not evaluated as Decodal roots, so a loader can parse an unsaved Markdown file into `HostValue` and immediately revalidate the open Decodal documents that import it.
+
 ## Structured imports
 
 `ImportLoader::load` returns either `LoadedImport::Source` or `LoadedImport::Value`.

doc/manual/souce/development.md

@@ -13,6 +13,18 @@ cargo check -p decodal --no-default-features
 nix flake check
 ```
 
+Run the default stdio language server with:
+
+```sh
+cargo run -q -p decodal-lsp
+```
+
+The protocol integration tests use an in-memory LSP connection and can be run independently:
+
+```sh
+cargo test -p decodal-lsp
+```
+
 Regex support is optional and should be tested explicitly when touched.
 
 ```sh
@@ -24,7 +36,7 @@ cargo run -q -p decodal-cli --features regex -- examples/regex/main.dcdl
 
 The primary crates.io package is `decodal`, which contains the embeddable library.
 `decodal-derive` provides optional derive macros for Rust struct integration and is published only when the derive crate changes.
-Workspace support crates such as `decodal-cli`, the Rust source crate `decodal-wasm`, and `decodal-language-tools` are not published to crates.io.
+Workspace support crates such as `decodal-cli`, the Rust source crate `decodal-wasm`, `decodal-language-tools`, and `decodal-lsp` are not published to crates.io.
 The generated WebAssembly package under `packages/decodal-wasm/` is published to npm and JSR.
 The CodeMirror package bundles the generated formatter WebAssembly from `decodal-language-tools`.
 The project is dual licensed as `MIT OR Apache-2.0`.