fix: ClickHouse insertion using native clickhouse-go/v2 API

- Replace database/sql wrapper with clickhouse.Open() and clickhouse.Conn
- Use PrepareBatch + Append + Send pattern for proper batch inserts
- Fix ATTEMPT_TO_READ_AFTER_EOF errors caused by empty VALUES
- Add batch size logging for debugging
- Update version to 1.1.5

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

Dockerfile

@@ -23,8 +23,7 @@ RUN go mod download || true
 COPY . .
 
 # Run tests with coverage (fail if < 80%)
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    go test -race -coverprofile=coverage.txt -covermode=atomic ./... && \
+RUN go test -race -coverprofile=coverage.txt -covermode=atomic ./... && \
     echo "=== Coverage Report ===" && \
     go tool cover -func=coverage.txt | grep total && \
     TOTAL=$(go tool cover -func=coverage.txt | grep total | awk '{gsub(/%/, "", $3); print $3}') && \
@@ -36,8 +35,7 @@ RUN --mount=type=cache,target=/root/.cache/go-build \
     echo "Coverage check passed!"
 
 # Build binary
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build \
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build \
     -ldflags="-w -s" \
     -o /usr/bin/logcorrelator \
     ./cmd/logcorrelator