feat(family-api): add FAMILIES const and family-taxonomy tests (#60)

* feat(family-api): add FAMILIES const and family-taxonomy tests

Introduce `wickra_core::FAMILIES`, a `&'static [(&str, &[&str])]` mapping
every built-in indicator to one of 16 families (Moving Averages, Momentum
Oscillators, Trend & Directional, Price Oscillators, Volatility & Bands,
Bands & Channels, Trailing Stops, Volume, Price Statistics, Ehlers /
Cycle (DSP), Pivots & S/R, DeMark, Ichimoku & Charts, Candlestick
Patterns, Market Profile, Risk / Performance).

Two compile-time-anchored guards make sure the const stays trustworthy:
- `no_duplicates_across_families`: no indicator is listed in two families
- `total_count_matches_expected`: hard-coded total bumps in lockstep with
  the indicator catalogue (214 today), so any new indicator added without
  being filed under a family trips the test.

Also corrects the module doc comment which falsely claimed
indicators were grouped by category internally; the `mod` block is
alphabetical, and the canonical taxonomy now lives in `FAMILIES`.

* chore: sync indicator count to 214

---------

Co-authored-by: wickra-bot <wickra-bot@users.noreply.github.com>

crates/wickra-core/src/lib.rs

@@ -83,7 +83,7 @@ pub use indicators::{
     VolumeOscillator, VolumePriceTrend, Vortex, VortexOutput, Vwap, VwapStdDevBands,
     VwapStdDevBandsOutput, Vwma, Vzo, WaveTrend, WaveTrendOutput, WeightedClose, WilliamsFractals,
     WilliamsFractalsOutput, WilliamsR, Wma, WoodiePivots, WoodiePivotsOutput, YangZhangVolatility,
-    YoyoExit, ZScore, ZeroLagMacd, ZeroLagMacdOutput, ZigZag, ZigZagOutput, Zlema, T3,
+    YoyoExit, ZScore, ZeroLagMacd, ZeroLagMacdOutput, ZigZag, ZigZagOutput, Zlema, FAMILIES, T3,
 };
 pub use ohlcv::{Candle, Tick};
 pub use traits::{BatchExt, Chain, Indicator};