ci: Add GitHub Actions workflows and fix test exports

Infrastructure improvements:

1. GitHub Actions CI workflow:
   - Test on Julia 1.10 (LTS) and latest stable
   - Ubuntu Linux runner
   - Code coverage via Codecov

2. Documentation build workflow:
   - Builds on push to master/main and PRs
   - Uses Documenter.jl with GitHub Pages deployment

3. Fix missing exports for tests:
   - Add Statistics to test dependencies

Tests still have API mismatches (49 failures) but infrastructure is now

.github/workflows/CI.yml

@@ -0,0 +1,45 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
+    branches:
+      - master
+      - main
+
+jobs:
+  test:
+    name: Julia ${{ matrix.version }} - ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        version:
+          - '1.10'  # LTS
+          - '1'     # Latest stable
+        os:
+          - ubuntu-latest
+        
+    steps:
+      - uses: actions/checkout@v4
+      
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: ${{ matrix.version }}
+          
+      - uses: julia-actions/cache@v2
+      
+      - uses: julia-actions/julia-buildpkg@v1
+      
+      - uses: julia-actions/julia-runtest@v1
+      
+      - uses: julia-actions/julia-processcoverage@v1
+      
+      - uses: codecov/codecov-action@v4
+        with:
+          files: lcov.info
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: false