refactor: Convert shell scripts to Bazel-native test infrastructure

Following RULE #1: THE BAZEL WAY FIRST from CLAUDE.md

Changes:
- Deleted shell script files (validate_bindgen_fix.sh, test_components_with_wasmtime.sh)
- Created alignment_test.bzl with custom Bazel test rule
- Enhanced test/alignment/BUILD.bazel with build_test and test_suite
- Enhanced test/integration/BUILD.bazel with wit_bindgen_rt_fix_test
- Added top-level test suite //:wit_bindgen_rt_validation
- Updated TESTING_SUMMARY.md to reflect Bazel-native approach

Testing Infrastructure:
1. alignment_validation_test - Custom test rule with:
   - wasm-tools validation
   - WIT interface extraction
   - Export and record structure verification
   - wasmtime instantiation testing
   - Hermetic runfiles and toolchain resolution

2. build_test - Validates component builds:
   - alignment_component_debug
   - alignment_component_release
   - service_a_component (previously failing)
   - service_b_component

3. test_suite - Aggregates related tests:
   - //test/alignment:alignment_tests
   - //test/integration:wit_bindgen_rt_fix_test
   - //:wit_bindgen_rt_validation (top-level)

All tests follow Bazel best practices:
- Custom test rules with test = True
- ctx.actions.write() for script generation
- Hermetic runfiles for tool access
- Toolchain-based tool resolution
- Cross-platform support (no Unix-specific commands)
- Zero shell script files

Run tests with:
  bazel test //:wit_bindgen_rt_validation

Author: claude

BUILD.bazel

@@ -4,6 +4,16 @@ load("@buildifier_prebuilt//:rules.bzl", "buildifier")
 
 package(default_visibility = ["//visibility:public"])
 
+# Test suite for wit-bindgen-rt fix validation
+# Aggregates alignment tests and integration tests that validate the fix
+test_suite(
+    name = "wit_bindgen_rt_validation",
+    tests = [
+        "//test/alignment:alignment_tests",
+        "//test/integration:wit_bindgen_rt_fix_test",
+    ],
+)
+
 # Export all rule files
 exports_files([
     "LICENSE",