🧪 test: add @wip tag for focused development

- Add @wip tag documentation to BDD_TAGS.md
- Modify all feature test suites to include @wip in tag filters
- Update test scripts to handle @wip tag inclusion
- @wip overrides exclusion tags (@todo, @skip, @flaky) for active development

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

scripts/test-feature.sh

@@ -110,7 +110,7 @@ run_feature_tests() {
     
     # Run tests with proper coverage measurement and tag exclusion
     set +e
-    test_output=$(go test ./features/${FEATURE}/... -tags=~@flaky,~@todo,~@skip -v -cover -coverpkg=./... -coverprofile=coverage-${FEATURE}.out 2>&1)
+    test_output=$(go test ./features/${FEATURE}/... -tags=~@flaky,~@todo,~@skip,@wip -v -cover -coverpkg=./... -coverprofile=coverage-${FEATURE}.out 2>&1)
     test_exit_code=$?
     set -e