feat(indicators): B3 Trend & Directional batch (413 -> 420) (#181)

Adds the **B3 — Trend & Directional** batch: seven new indicators, taking the
catalog from 413 to 420 (Trend & Directional family).

| Indicator | Input → Output | Summary |
|-----------|----------------|---------|
| `Qstick` | candle → f64 | Chande's SMA of the candle body (close − open) |
| `TtmTrend` | candle → f64 (±1) | John Carter close-vs-median-SMA trend filter |
| `TrendStrengthIndex` | f64 → f64 | signed r² of an OLS regression of price vs time |
| `PolarizedFractalEfficiency` | f64 → f64 | Hannula directional trend efficiency |
| `WavePm` | f64 → f64 | Kase variance-normalised peak-momentum statistic (reconstruction) |
| `GatorOscillator` | candle → struct | Bill Williams Alligator convergence/divergence histogram |
| `KasePermissionStochastic` | candle → struct | double-smoothed stochastic permission filter |

Note: the roadmap's "Directional Indicator +DI/−DI" item is already covered by
the existing standalone `PlusDi` / `MinusDi` / `Dx`, so it is intentionally not
re-added.

All touchpoints wired: core (every-branch unit tests), Python/Node/WASM
bindings, fuzz drivers, Python test registries + reference tests, Node
factories, README/CHANGELOG counters.

Local verify: `cargo test -p wickra-core` (lib 3389 + doc 378), `cargo clippy
--workspace --all-targets --all-features -- -D warnings`, node build + 495
tests, maturin + 815 pytest, counter 420 == 420.

docs/README.md

@@ -8,7 +8,7 @@ That includes:
   [Python](https://docs.wickra.org/Quickstart-Python),
   [Node](https://docs.wickra.org/Quickstart-Node), and
   [WASM](https://docs.wickra.org/Quickstart-WASM).
-- A per-indicator deep dive for every one of the **413 indicators** across
+- A per-indicator deep dive for every one of the **420 indicators** across
   the sixteen families (Moving Averages, Momentum Oscillators, Trend &
   Directional, Price Oscillators, Volatility & Bands, Bands & Channels,
   Trailing Stops, Volume, Price Statistics, Ehlers / Cycle DSP, Pivots &