test: 100% coverage for rsi + accelerator_oscillator + aroon + atr_trailing_stop + chaikin_oscillator (#28)

* test(rsi): cover period/value accessors, name, naive flat-series branch

Codecov flagged 7 lines in indicators/rsi.rs (file at 96.42%): const
accessors period (60-62), value (65-67), Indicator-impl name (145-147),
and line 167 in the test-helper rsi_naive's ag==0 fallback. The
proptest reference never lands on a fully flat series so the helper's
50.0 branch was dead.

Add accessors_and_metadata covering period/value/name and
naive_helper_flat_series_yields_50 driving rsi_naive on [42.0; 20] —
both avg_gain and avg_loss converge to 0, hitting the 50.0 branch.
rsi.rs now at 196/196.

* test(accelerator_oscillator): cover params accessor + name metadata

Codecov flagged 6 lines in indicators/accelerator_oscillator.rs (file
at 93.68%): const accessor params (69-71) and Indicator-impl name
(99-101). ac.rs now at 95/95.

* test(aroon): cover period accessor + name metadata

Codecov flagged 6 lines in indicators/aroon.rs (file at 94.28%): const
accessor period (56-58) and Indicator-impl name (104-106). aroon.rs
now at 105/105.

* test(atr_trailing_stop): cover params accessor + name metadata

Codecov flagged 6 lines in indicators/atr_trailing_stop.rs (file at
95.91%): const accessor params (77-79) and Indicator-impl name
(130-132). atr_trailing_stop.rs now at 147/147.

* test(chaikin_oscillator): cover periods accessor + name metadata

Codecov flagged 6 lines in indicators/chaikin_oscillator.rs (file at
95.27%): const accessor periods (76-78) and Indicator-impl name
(109-111). chaikin_oscillator.rs now at 127/127.

crates/wickra-core/src/indicators/rsi.rs

@@ -202,6 +202,34 @@ mod tests {
         assert!(matches!(Rsi::new(0), Err(Error::PeriodZero)));
     }
 
+    /// Cover the const accessors `period` / `value` (60-67) and the
+    /// Indicator-impl `name` body (145-147). `warmup_period` is covered
+    /// already by `warmup_period_is_period_plus_one`.
+    #[test]
+    fn accessors_and_metadata() {
+        let mut rsi = Rsi::new(14).unwrap();
+        assert_eq!(rsi.period(), 14);
+        assert_eq!(rsi.name(), "RSI");
+        assert_eq!(rsi.value(), None);
+        for i in 1..=15 {
+            rsi.update(100.0 + f64::from(i));
+        }
+        assert!(rsi.value().is_some());
+    }
+
+    /// Cover the `ag == 0` branch (line 167) of the test-helper `rsi_naive`:
+    /// when both `avg_gain` and `avg_loss` are 0 (a perfectly flat series),
+    /// the helper must return the neutral 50.0. The proptest reference uses
+    /// random inputs that essentially never hit zero gains AND zero losses
+    /// simultaneously, leaving this branch dead in the helper.
+    #[test]
+    fn naive_helper_flat_series_yields_50() {
+        let ks = rsi_naive(&[42.0; 20], 5);
+        for r in ks.into_iter().skip(5) {
+            assert_eq!(r.expect("ready after period+1 inputs"), 50.0);
+        }
+    }
+
     #[test]
     fn warmup_period_is_period_plus_one() {
         let rsi = Rsi::new(14).unwrap();