ci: add pool shutdown regression tests and PR CI workflow

Add 19 tests in core/pool/pool_test.go covering:
- addAddition: normal, after cancel, wg balance, full buffer, concurrent
- sendProcess: normal, after cancel, full buffer, concurrent
- putToOutput/putToFuzzy: normal, after cancel, Outwg balance
- Handler lifecycle: processCh close exits handler, drains all items
- Shutdown sequence: no deadlock, cancel mid-flight
- Goroutine leak detection after full shutdown

Add .github/workflows/ci.yml:
- Runs on PR to master and push to master
- Tests on ubuntu-latest and windows-latest
- go build, go test -race, go vet

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: M09Ic

.github/workflows/ci.yml

@@ -0,0 +1,34 @@
+name: CI
+
+on:
+  pull_request:
+    branches: [ master ]
+  push:
+    branches: [ master ]
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.20"
+
+      - name: Build
+        run: go build ./...
+
+      - name: Test (race)
+        run: go test ./core/pool/ ./core/baseline/ ./core/ihttp/ ./pkg/ -v -race -count=1 -timeout=120s
+
+      - name: Vet
+        run: go vet ./core/... ./pkg/... ./cmd/...
+        continue-on-error: true