Add qemu based github actions test

Author: dmtrKovalenko

.github/workflows/riscv-qemu.yml

@@ -0,0 +1,39 @@
+name: RISC-V QEMU Tests
+
+on:
+  pull_request:
+    # paths:
+    #   - 'src/rvv.c'
+    #   - 'src/diff.zig'
+    #   - 'src/test_color_delta.zig'
+  push:
+    branches: [main, feat/riscv]
+
+jobs:
+  riscv-qemu:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Zig
+        uses: mlugg/setup-zig@v2
+        with:
+          version: 0.15.1
+
+      - name: Install QEMU
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y qemu-user-static
+
+      - name: Build RISC-V with RVV
+        run: |
+          zig build -Dtarget=riscv64-linux-gnu -Doptimize=ReleaseFast
+
+      - name: Run RVV tests
+        run: |
+          qemu-riscv64-static -cpu help
+          qemu-riscv64-static -cpu generic_rv64,v=true,vlen=128,elen=64 \
+            zig-out/bin/odiff test/png/orange.png test/png/orange_changed.png /tmp/rvv-test.png
+
+          # Verify output was created
+          [ -f /tmp/rvv-test.png ] && echo "✅ Done" || exit 1