ci: build and test on push; keep memo merge out of assert

The memo test performed its group merge inside assert(), which
NDEBUG strips in Release builds, so the merged-group validation
terminated. The call now runs unconditionally with its result
checked. Adds the two-platform build-and-test workflow and the
README badge.

Author: Aly700

.github/workflows/ci.yml

@@ -0,0 +1,22 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  build-and-test:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Configure
+        run: cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
+      - name: Build
+        run: cmake --build build --parallel
+      - name: Test
+        run: ctest --test-dir build --output-on-failure

README.md

@@ -1,5 +1,7 @@
 # Vectorized SQL Query Engine
 
+[![CI](https://github.com/Aly700/vectorized-sql-engine/actions/workflows/ci.yml/badge.svg)](https://github.com/Aly700/vectorized-sql-engine/actions/workflows/ci.yml)
+
 ## Scope
 
 A columnar analytical engine whose hardest boundary is the optimizer: SQL is parsed and bound into relational algebra, rules produce equivalent plans, and a Cascades-style memo chooses a low-cost vectorized physical plan without changing semantics.

tests/memo.cpp

@@ -202,7 +202,8 @@ void assert_cross_group_duplicate_expression_merges_groups() {
     assert(left_right != right_left);
 
     try {
-        assert(memo.insert_equivalent(left_right, join_expression(right, left)));
+        const auto merged = memo.insert_equivalent(left_right, join_expression(right, left));
+        assert(merged);
     } catch (const std::logic_error& error) {
         std::cerr << "cross-group duplicate did not merge\n"
                   << "error: " << error.what() << "\n"