Add CI workflow for SIL build and tests

Author: dfeen87

.github/workflows/ci.yml

@@ -0,0 +1,27 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up build toolchain
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y --no-install-recommends build-essential cmake
+
+      - name: Configure SIL tests
+        run: cmake -S tests/sil -B build
+
+      - name: Build SIL tests
+        run: cmake --build build
+
+      - name: Run SIL tests
+        run: ctest --test-dir build --output-on-failure

README.md

@@ -218,6 +218,27 @@ Typical flow:
 
 ---
 
+## Continuous Integration
+
+CI provides a fast, deterministic check for build correctness and core simulation invariants.
+
+**What CI checks**
+- Configures and builds the SIL test harness (CMake).
+- Runs the SIL fault-injection smoke tests to validate deterministic safety behavior.
+
+**What CI intentionally does not check**
+- Hardware-in-the-loop (HIL) or physical testbed validation.
+- Integration tests that depend on external infrastructure or network services.
+
+**Reproduce CI locally**
+```bash
+cmake -S tests/sil -B build
+cmake --build build
+ctest --test-dir build --output-on-failure
+```
+
+---
+
 ## Operational flow (how it behaves)
 
 1. **Snapshot** current state (Ψ) and derived informational health state (Φ)