fix: reject out-of-range led brightness instead of silently clamping

led accepted any u16 and main.rs clamped to 0..=1000 with no feedback,
inconsistent with sidetone which rejects out-of-range at parse time.
Add a clap range validator (0..=1000) and drop the silent clamp, so
invalid input now fails loudly.

Further quality-audit follow-ups:
- remove dead BragiDevice::open() (no caller; binary uses open_with_verbose)
- add tests: led range validation, format_battery for all status
  variants, waybar "unknown" class

Bump 0.1.2 -> 0.1.3.

tests/cli_test.rs

@@ -44,3 +44,15 @@ fn sidetone_without_value_is_read_mode() {
     let result = parse_args(&["corsairctl", "sidetone"]);
     assert!(result.is_ok());
 }
+
+#[test]
+fn led_rejects_above_1000() {
+    let result = parse_args(&["corsairctl", "led", "1001"]);
+    assert!(result.is_err());
+}
+
+#[test]
+fn led_accepts_max() {
+    let result = parse_args(&["corsairctl", "led", "1000"]);
+    assert!(result.is_ok());
+}