feat(history): atuin history support (#134)

closes #91

3 mode config atuin history
```toml
[core]
# 0 = off, 1 = atuin history only, 2 = atuin history + default history
atuin-history = 0
```
Default is Mode 0 (turn off), who uses atuin history has to config it
manually

Mode 1 = atuin only (as you can see only 11 commands):
<img width="1285" height="466" alt="image"
src="https://github.com/user-attachments/assets/ca520ec7-fb45-4403-8087-a4951ba8dba0"
/>

Mode 2 = combine shell history + atuin history (prefer atuin):
<img width="1261" height="469" alt="image"
src="https://github.com/user-attachments/assets/1558ad3e-38f3-4d6e-bc8e-cfc00ea9cb4b"
/>

Mode 0 = turn off atuin

---
Custom atuin db path if anyone's using their own path (leave empty to
use default from atuin)
```toml
atuin-db-path = ""
```

---

I also handled the search menu overlay of Atuin, IRIS won't show in this
mode, but you have to change the keybind between 2 tool cuz they're
using same keybind Ctrl + R, but I think using IRIS make it unnecessary
to use Atuin search mode (82b180c9610f75d41008a54dfde474c7f2cce015)


<img width="70%" alt="image"
src="https://github.com/user-attachments/assets/e0c62050-7e6e-4e37-a1cc-2bfb63e1e984"
/>

<i><b>Before (Menu layout completely broken)</b></i>

<img width="50%" alt="image"
src="https://github.com/user-attachments/assets/1e6d8de9-cde8-473d-8a42-4748c480c812"
/>

<i ><b>After handling (not shows anymore)</b></i>

internal/config/config.go

@@ -40,6 +40,9 @@ type CoreConfig struct {
 	Debug       bool   `toml:"debug"`
 	ExpandAlias bool   `toml:"expand-alias"`
 	AutoExecute bool   `toml:"auto-execute"`
+	// 0 = shell history, 1 = atuin only, 2 = atuin + shell
+	Atuin       int    `toml:"atuin-history"`
+	AtuinDBPath string `toml:"atuin-db-path"`
 }
 
 type UIConfig struct {

internal/config/paths.go

@@ -49,6 +49,21 @@ func HistoryDBPath() (string, error) {
 	return filepath.Join(filepath.Dir(statePath), "history.db"), nil
 }
 
+func AtuinDBPath() (string, error) {
+	if cfg := Get(); cfg != nil && cfg.Core.AtuinDBPath != "" {
+		return cfg.Core.AtuinDBPath, nil
+	}
+	dataHome := os.Getenv("XDG_DATA_HOME")
+	if dataHome == "" {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return "", err
+		}
+		dataHome = filepath.Join(home, ".local", "share")
+	}
+	return filepath.Join(dataHome, "atuin", "history.db"), nil
+}
+
 func CachePath() (string, error) {
 	cacheHome := os.Getenv("XDG_CACHE_HOME")
 	if cacheHome != "" {