feat(ci): add --typescript-only flag to skip Python tests in integration test script

The TypeScript client CI workflow currently fails because it depends on Python
tests passing first, but version mismatches between llama-stack client versions
can cause Python tests to fail even when the TypeScript client is working fine.

This adds a `--typescript-only` flag to scripts/integration-tests.sh that:
- Skips pytest execution entirely when enabled
- Still starts the Llama Stack server (required for TS client tests)
- Proceeds directly to running TypeScript client tests

The TypeScript client can now be tested independently by calling:
  ./scripts/integration-tests.sh --stack-config server:ci-tests --typescript-only

Test plan: Verified flag parsing, conditional pytest skip, and help text update.

scripts/integration-tests.sh

@@ -20,6 +20,7 @@ TEST_PATTERN=""
 INFERENCE_MODE="replay"
 EXTRA_PARAMS=""
 COLLECT_ONLY=false
+TYPESCRIPT_ONLY=false
 
 # Function to display usage
 usage() {
@@ -34,6 +35,7 @@ Options:
     --subdirs STRING         Comma-separated list of test subdirectories to run (overrides suite)
     --pattern STRING         Regex pattern to pass to pytest -k
     --collect-only           Collect tests only without running them (skips server startup)
+    --typescript-only        Skip Python tests and run only TypeScript client tests
     --help                   Show this help message
 
 Suites are defined in tests/integration/suites.py and define which tests to run.
@@ -90,6 +92,10 @@ while [[ $# -gt 0 ]]; do
         COLLECT_ONLY=true
         shift
         ;;
+    --typescript-only)
+        TYPESCRIPT_ONLY=true
+        shift
+        ;;
     --help)
         usage
         exit 0
@@ -544,7 +550,9 @@ if [[ -n "$STACK_CONFIG" ]]; then
     STACK_CONFIG_ARG="--stack-config=$STACK_CONFIG"
 fi
 
-pytest -s -v $PYTEST_TARGET \
+# Run Python tests unless typescript-only mode
+if [[ "$TYPESCRIPT_ONLY" == "false" ]]; then
+    pytest -s -v $PYTEST_TARGET \
         $STACK_CONFIG_ARG \
         --inference-mode="$INFERENCE_MODE" \
         -k "$PYTEST_PATTERN" \
@@ -553,7 +561,12 @@ pytest -s -v $PYTEST_TARGET \
         --embedding-model=sentence-transformers/nomic-ai/nomic-embed-text-v1.5 \
         --color=yes $EXTRA_PARAMS \
         --capture=tee-sys
-exit_code=$?
+    exit_code=$?
+else
+    echo "Skipping Python tests (--typescript-only mode)"
+    exit_code=0
+fi
+
 set +x
 set -e