fix: address review feedback on transport selection and shell arg forwarding

- Normalize MCP_MODE to lowercase in client constructor so that
  MCP_MODE=STDIO works the same as MCP_MODE=stdio
- Select stdio transport by default; only use HTTP when MCP_MODE === "http"
  (previously any non-"stdio" value fell through to HTTP)
- Add shift 2 in run_tests_in_mode() so mode_name and enable_monitoring
  positional args are not forwarded to node as extra CLI arguments

Co-authored-by: data-douser <70299490+data-douser@users.noreply.github.com>

Author: Copilot

client/scripts/run-integration-tests.sh

@@ -97,6 +97,7 @@ fi
 run_tests_in_mode() {
     local mode_name="$1"
     local enable_monitoring="$2"
+    shift 2
 
     echo ""
     echo "═══════════════════════════════════════════════════════════════"

client/src/ql-mcp-client.js

@@ -37,7 +37,7 @@ class CodeQLMCPClient {
   constructor(options = {}) {
     this.client = null;
     this.transport = null;
-    this.mcpMode = process.env.MCP_MODE || "stdio";
+    this.mcpMode = (process.env.MCP_MODE || "stdio").toLowerCase();
     this.serverUrl = process.env.MCP_SERVER_URL || DEFAULT_SERVER_URL;
     this.timeout = parseInt(options.timeout || process.env.TIMEOUT_SECONDS || "30") * 1000;
     this.logger = new TestLogger();
@@ -122,7 +122,7 @@ class CodeQLMCPClient {
         version: "1.0.0"
       });
 
-      if (this.mcpMode === "stdio") {
+      if (this.mcpMode !== "http") {
         const repoRoot = path.join(__dirname, "..", "..");
         const serverPath =
           process.env.MCP_SERVER_PATH ||