feat(coder): add LSP code intelligence tools

- lsp/ module: types, config, JSON-RPC client, server-manager, operations
- lsp_diagnostics: TypeScript/JavaScript diagnostics for a file
- lsp_goto_definition: find symbol definition at position
- lsp_find_references: find all references to a symbol
- Registered as READ_TOOLS in tool index

apps/coder/src/services/lsp/config.ts

@@ -0,0 +1,19 @@
+export interface LspServerConfig {
+  command: string;
+  args: string[];
+  rootPatterns: string[];
+}
+
+const TS_CONFIG: LspServerConfig = {
+  command: 'typescript-language-server',
+  args: ['--stdio'],
+  rootPatterns: ['package.json', 'tsconfig.json'],
+};
+
+const SUPPORTED_EXTS = new Set(['ts', 'tsx', 'js', 'jsx', 'mjs', 'cjs']);
+
+export function getServerConfig(filePath: string): LspServerConfig | null {
+  const ext = filePath.split('.').pop()?.toLowerCase();
+  if (ext && SUPPORTED_EXTS.has(ext)) return TS_CONFIG;
+  return null;
+}