fix(lsp): improve code quality in directory diagnostics

- Dedupe directory-checking logic: findWorkspaceRoot now uses isDirectoryPath helper
- Add early return when no files match extension to avoid starting LSP server unnecessarily

src/tools/lsp/directory-diagnostics.ts

@@ -84,6 +84,15 @@ export async function aggregateDiagnosticsForDirectory(
   const wasCapped = allFiles.length > maxFiles
   const filesToProcess = allFiles.slice(0, maxFiles)
 
+  if (filesToProcess.length === 0) {
+    return [
+      `Directory: ${absDir}`,
+      `Extension: ${extension}`,
+      `Files scanned: 0`,
+      `No files found with extension "${extension}".`,
+    ].join("\n")
+  }
+
   const root = findWorkspaceRoot(absDir)
 
   const allDiagnostics: Diagnostic[] = []

src/tools/lsp/lsp-client-wrapper.ts

@@ -6,10 +6,21 @@ import { LSPClient, lspManager } from "./client"
 import { findServerForExtension } from "./config"
 import type { ServerLookupResult } from "./types"
 
+export function isDirectoryPath(filePath: string): boolean {
+  if (!existsSync(filePath)) {
+    return false
+  }
+  return statSync(filePath).isDirectory()
+}
+
+export function uriToPath(uri: string): string {
+  return fileURLToPath(uri)
+}
+
 export function findWorkspaceRoot(filePath: string): string {
   let dir = resolve(filePath)
 
-  if (!existsSync(dir) || !require("fs").statSync(dir).isDirectory()) {
+  if (!existsSync(dir) || !isDirectoryPath(dir)) {
     dir = require("path").dirname(dir)
   }
 
@@ -29,17 +40,6 @@ export function findWorkspaceRoot(filePath: string): string {
   return require("path").dirname(resolve(filePath))
 }
 
-export function uriToPath(uri: string): string {
-  return fileURLToPath(uri)
-}
-
-export function isDirectoryPath(filePath: string): boolean {
-  if (!existsSync(filePath)) {
-    return false
-  }
-  return statSync(filePath).isDirectory()
-}
-
 export function formatServerLookupError(result: Exclude<ServerLookupResult, { status: "found" }>): string {
   if (result.status === "not_installed") {
     const { server, installHint } = result