feat(lsp): add code actions, signature help, and document highlights

Assisted-by: MiMo V2.5 Pro

lsp/server.go

@@ -131,7 +131,10 @@ func (s *Server) dispatch(msg *rpcMessage) (exit bool) {
 					},
 					"full": true,
 				},
-				InlayHintProvider: true,
+				InlayHintProvider:         true,
+				DocumentHighlightProvider: true,
+				CodeActionProvider:        true,
+				SignatureHelpProvider:     map[string]any{"triggerCharacters": []string{"("}},
 			},
 			ServerInfo: map[string]string{"name": "gasm", "version": "0.31.1"},
 		})
@@ -205,6 +208,21 @@ func (s *Server) dispatch(msg *rpcMessage) (exit bool) {
 		json.Unmarshal(msg.Params, &p)
 		s.respond(msg.ID, s.inlayHints(p))
 
+	case "textDocument/codeAction":
+		var p codeActionParams
+		json.Unmarshal(msg.Params, &p)
+		s.respond(msg.ID, s.codeActions(p))
+
+	case "textDocument/signatureHelp":
+		var p signatureHelpParams
+		json.Unmarshal(msg.Params, &p)
+		s.respond(msg.ID, s.signatureHelp(p))
+
+	case "textDocument/documentHighlight":
+		var p documentHighlightParams
+		json.Unmarshal(msg.Params, &p)
+		s.respond(msg.ID, s.documentHighlights(p))
+
 	case "textDocument/semanticTokens/full":
 		var p semanticTokensParams
 		json.Unmarshal(msg.Params, &p)