feat(lsp): add config-driven LSP support (Roblox Luau via luau-lsp)

Add Language Server Protocol integration modeled on opencode's, wired for
this codebase's plain-TypeScript tool/agent architecture.

Core (@dispatch/core):
- lsp/client.ts: LSP/JSON-RPC client over stdio (vscode-jsonrpc) with the
  initialize handshake, didOpen/didChange sync, push + pull diagnostics
  (textDocument/diagnostic, workspace/diagnostic), and a generic request()
  passthrough for hover/definition/references/documentSymbol.
- lsp/server.ts: resolves dispatch.toml [lsp] entries into spawn specs.
  Config-driven only — no builtin registry, no auto-download.
- lsp/manager.ts: process-wide LspManager owning client lifecycles, keyed
  by root+serverID, lazy spawn + reuse + graceful shutdown.
- lsp/language.ts: extension->languageId map incl. .luau -> "luau".
- lsp/diagnostic.ts: error-only <diagnostics> block formatting (1-based).
- tools/lsp.ts: on-demand 'lsp' tool (1-based coords -> 0-based wire).
- write-file.ts: optional onAfterWrite hook for diagnostics-on-write.
- config schema: validate [lsp] block; DispatchConfig.lsp + LspServerConfig.

API (@dispatch/api):
- AgentManager owns one LspManager; per-working-directory server cache
  cleared on config reload; diagnostics appended to write_file results;
  'lsp' tool gated by new perm_lsp setting; shutdownAll on destroy().

Config:
- dispatch.toml: documented, commented [lsp.luau-lsp] Roblox example.

Tests: fake-lsp-server fixture + client/manager/server/diagnostic/schema/
tool/write-hook suites, plus an opt-in real-binary luau-lsp smoke test
(auto-skipped when luau-lsp is absent). 652 pass; biome + 3 typechecks green.

1 files changed, 14 insertions, 1 deletions

diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 8334102..8608b6a 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -68,6 +68,18 @@ export {
 	logStreamEvent,
 } from "./llm/debug-logger.js";
 export { createProvider } from "./llm/provider.js";
+// LSP (Language Server Protocol)
+export {
+	createLspClient,
+	type Diagnostic as LspDiagnostic,
+	type LspClient,
+	LspManager,
+	type LspServerHandle,
+	pretty as prettyDiagnostic,
+	type ResolvedLspServer,
+	report as reportDiagnostics,
+	resolveServersFromConfig,
+} from "./lsp/index.js";
 // Models
 export {
 	getModelsCatalog,
@@ -88,6 +100,7 @@ export {
 export { prefix as bashArityPrefix } from "./tools/bash-arity.js";
 // Tools
 export { createListFilesTool } from "./tools/list-files.js";
+export { createLspTool, type LspToolContext } from "./tools/lsp.js";
 export { createReadFileTool } from "./tools/read-file.js";
 export { createReadFileSliceTool } from "./tools/read-file-slice.js";
 export { createReadTabTool, type ReadTabCallbacks } from "./tools/read-tab.js";
@@ -111,7 +124,7 @@ export {
 export { createTaskListTool, TaskList, TODO_DESCRIPTION } from "./tools/task-list.js";
 export { clearSpillForTab } from "./tools/truncate.js";
 export { createWebSearchTool } from "./tools/web-search.js";
-export { createWriteFileTool } from "./tools/write-file.js";
+export { type AfterWriteHook, createWriteFileTool } from "./tools/write-file.js";
 export {
 	BackgroundTranscriptStore,
 	createYoutubeTranscribeTool,