chore: Simplify logo and add GitHub Actions CI workflow

- Remove all text and decorative elements from eval_ex.svg, keeping only the core hexagonal logo with gradient fills
- Add GitHub Actions CI workflow for automated testing on push/PR to master branch
- CI runs on Elixir 1.18 and OTP 27 with dependency caching
- Enforces compilation with --warnings-as-errors to maintain code quality

Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: nshkrdotcom

.github/workflows/ci.yml

@@ -0,0 +1,42 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: Test on Elixir 1.18 and OTP 27
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Elixir
+        uses: erlef/setup-beam@v1
+        with:
+          elixir-version: '1.18'
+          otp-version: '27'
+
+      - name: Restore dependencies cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            deps
+            _build
+          key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
+          restore-keys: ${{ runner.os }}-mix-
+
+      - name: Install dependencies
+        run: mix deps.get
+
+      - name: Compile with warnings as errors
+        run: mix compile --warnings-as-errors
+
+      - name: Run tests
+        run: mix test