feat(config): add some more config options (#64)

## Add
Make these things configurable
- Expand aliases
- Suggest hidden files (#59)
- Toggle menu and mode 

```
[ui]
hidden-files = true # or false

[core]
expand-alias = true # or false

[keybindings]
toggle-mode = "ctrl+r"
toggle-menu = "ctrl+space"
```

- Auto reload config on changes: now just changes config and save the
file, IRIS will auto detect and reload in silent
- Added all these in config on init and docs

## Fix
I tested on holding backspace and the ghost text keep glitching so I
fixed it, this is just a small fix

internal/config/keys.go

@@ -0,0 +1,64 @@
+package config
+
+import (
+	"strings"
+)
+
+// MatchKey matches a sequence of terminal bytes against a configured key string.
+// Key strings can be e.g. "ctrl+r", "tab", "shift+tab", "right".
+// Returns matched=true if the byte sequence matches the configured key, and consumed=number of bytes to consume.
+func MatchKey(input []byte, expected string) (matched bool, consumed int) {
+	if len(input) == 0 {
+		return false, 0
+	}
+
+	expected = strings.ToLower(strings.TrimSpace(expected))
+
+	if strings.HasPrefix(expected, "ctrl+") && len(expected) == 6 {
+		char := expected[5]
+		if char >= 'a' && char <= 'z' {
+			targetByte := char - 'a' + 1
+			if input[0] == targetByte {
+				return true, 1
+			}
+		}
+	}
+
+	switch expected {
+	case "ctrl+space":
+		if input[0] == 0x00 {
+			return true, 1
+		}
+	case "tab":
+		if input[0] == 0x09 {
+			return true, 1
+		}
+	case "shift+tab":
+		// typically \033[Z
+		if len(input) >= 3 && input[0] == 0x1b && input[1] == '[' && input[2] == 'Z' {
+			return true, 3
+		}
+	case "right":
+		// typically \033[C or \033OC
+		if len(input) >= 3 && input[0] == 0x1b && (input[1] == '[' || input[1] == 'O') && input[2] == 'C' {
+			return true, 3
+		}
+	case "enter":
+		if input[0] == 0x0d || input[0] == 0x0a {
+			return true, 1
+		}
+	}
+
+	return false, 0
+}
+
+// FormatKeyName takes a config key string like "ctrl+r" and formats it for UI display, e.g. "<Ctrl+R>".
+func FormatKeyName(key string) string {
+	parts := strings.Split(key, "+")
+	for i, p := range parts {
+		if len(p) > 0 {
+			parts[i] = strings.ToUpper(p[:1]) + strings.ToLower(p[1:])
+		}
+	}
+	return "<" + strings.Join(parts, "+") + ">"
+}