Add readme

Author: auxten

REAEME.md

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+<a href="https://chdb.io" target="_blank">
+  <img src="https://avatars.githubusercontent.com/u/132536224" width=130 />
+</a>
+
+[![chDB-go](https://github.com/chdb-io/chdb-go/actions/workflows/chdb.yml/badge.svg)](https://github.com/chdb-io/chdb-go/actions/workflows/chdb.yml)
+
+# chdb-go
+[chDB](https://github.com/chdb-io/chdb) go bindings and chDB cli.
+
+## Install
+
+1. Download and install [`libchdb`](https://github.com/chdb-io/chdb/releases)
+  - run `make update_libchdb` to download and extract libchdb.so. or
+  - run `make install` to install libchdb.so
+2. Build `chdb-go`
+  - run `make build`
+3. Run `chdb-go` with or without persistent `--path`
+  - run `./chdb-go`
+
+## chdb-go CLI
+
+1. Simple mode
+```bash
+./chdb-go "SELECT 123"
+./chdb-go "SELECT 123" JSON
+```
+2. Interactive mode
+```bash
+./chdb-go # enter interactive mode, but data will be lost after exit
+./chdb-go --path /tmp/chdb # interactive persistent mode
+```
+
+#### Go lib Example
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/chdb-io/chdb-go/chdb"
+)
+
+func main() {
+    // Stateless Query (ephemeral)
+    result := chdb.Query("SELECT version()", "CSV")
+    fmt.Println(result)
+
+    // Stateful Query (persistent)
+    session, _ := NewSession(path)
+    defer session.Cleanup()
+
+    session.Query("CREATE DATABASE IF NOT EXISTS testdb; " +
+    "CREATE TABLE IF NOT EXISTS testdb.testtable (id UInt32) ENGINE = MergeTree() ORDER BY id;")
+
+    session.Query("USE testdb; INSERT INTO testtable VALUES (1), (2), (3);")
+
+    ret := session.Query("SELECT * FROM testtable;")
+    fmt.Println(ret)
+}
+```
+
+### Golang API docs
+
+- See [lowApi.md](lowApi.md) for the low level APIs.
+- See [chdb.md](chdb.md) for high level APIs.