feat: add TBF (Ehlers Truncated BandPass Filter) + fix all 64 warnings

TBF indicator:
- Sealed class with RingBuffer, stackalloc scratch, O(Length) per bar
- 7 core files: Tbf.cs, Tbf.Quantower.cs, Tbf.md, tbf.pine, 3 test files
- 67 tests (48 lib + 19 Quantower) all passing
- Full integration: sidebar, indexes, docs, Python bridge, exports

AMFM fix:
- Added envBuf.Clear()/smaBuf.Clear() after stackalloc in Batch
  (SkipLocalsInit garbage values caused 8.97e+65 blowup)

Warning fixes (64 → 0):
- Amfm.cs: S125 commented code removed, 11× IDE0011 braces
- Pta.cs: 11× IDE0011 braces on if/else/for/foreach
- Pta.Tests.cs: 14× IDE0011, S1481 unused var, S2699 assertion, 2× MA0074
- Lpf.Quantower.Tests.cs: 2× MA0074 StringComparison

Build: 0 warnings, 0 errors, 20,048 tests passing

python/quantalib/_bridge.py

@@ -331,6 +331,7 @@ HAS_RMED = _bind("qtl_rmed", [_dp, _dp, _ci, _ci])
 HAS_ROOFING = _bind("qtl_roofing", [_dp, _dp, _ci, _ci, _ci])
 HAS_SGF = _bind("qtl_sgf", [_dp, _dp, _ci, _ci, _ci])
 HAS_SPBF = _bind("qtl_spbf", [_dp, _dp, _ci, _ci, _ci, _ci])
+HAS_TBF = _bind("qtl_tbf", [_dp, _dp, _ci, _ci, _cd, _ci])
 HAS_SSF2 = _bind("qtl_ssf2", [_dp, _dp, _ci, _ci])
 HAS_SSF3 = _bind("qtl_ssf3", [_dp, _dp, _ci, _ci, _cd])
 HAS_USF = _bind("qtl_usf", [_dp, _dp, _ci, _ci])

python/quantalib/channels.py

@@ -257,8 +257,8 @@ def ttm_lrc(close: object, period: int = 14, offset: int = 0, **kwargs) -> objec
     return _wrap_multi({"midline": midline, "upper1": upper1, "lower1": lower1, "upper2": upper2, "lower2": lower2}, idx, "channels", offset)
 
 
-def ubands(close: object, period: int = 14, multiplier: float = 2.0, offset: int = 0, **kwargs) -> object:
-    """Upper/Lower Bands."""
+def ubands(close: object, period: int = 20, multiplier: float = 1.0, offset: int = 0, **kwargs) -> object:
+    """Ehlers Ultimate Bands."""
     period = int(kwargs.get("length", period))
     multiplier = float(multiplier)
     offset = int(offset)
@@ -271,8 +271,8 @@ def ubands(close: object, period: int = 14, multiplier: float = 2.0, offset: int
     return _wrap_multi({"upper": upper, "middle": middle, "lower": lower}, idx, "channels", offset)
 
 
-def uchannel(high: object, low: object, close: object, strPeriod: int = 14, centerPeriod: int = 20, multiplier: float = 2.0, offset: int = 0, **kwargs) -> object:
-    """Ulcer Channel."""
+def uchannel(high: object, low: object, close: object, strPeriod: int = 20, centerPeriod: int = 20, multiplier: float = 1.0, offset: int = 0, **kwargs) -> object:
+    """Ehlers Ultimate Channel."""
     strPeriod = int(strPeriod)
     centerPeriod = int(centerPeriod)
     multiplier = float(multiplier)

python/quantalib/filters.py

@@ -25,6 +25,7 @@ __all__ = [
     "roofing",
     "sgf",
     "spbf",
+    "tbf",
     "ssf2",
     "ssf3",
     "usf",
@@ -248,6 +249,19 @@ def spbf(close: object, shortPeriod: int = 40, longPeriod: int = 60, rmsPeriod:
     return _wrap(output, idx, f"SPBF_{shortPeriod}", "filters", offset)
 
 
+def tbf(close: object, period: int = 20, bandwidth: float = 0.1, length: int = 10, offset: int = 0, **kwargs) -> object:
+    """Ehlers Truncated Bandpass Filter."""
+    period = int(period)
+    bandwidth = float(bandwidth)
+    length = int(length)
+    offset = int(offset)
+    src, idx = _arr(close)
+    n = len(src)
+    output = _out(n)
+    _check(_lib.qtl_tbf(_ptr(src), _ptr(output), n, period, bandwidth, length))
+    return _wrap(output, idx, f"TBF_{period}", "filters", offset)
+
+
 def ssf2(close: object, period: int = 14, offset: int = 0, **kwargs) -> object:
     """Super Smoother (2-pole)."""
     period = int(kwargs.get("length", period))

python/src/Exports.Generated.cs

@@ -2887,6 +2887,22 @@ public static unsafe partial class Exports
         catch { return StatusCodes.QTL_ERR_INTERNAL; }
     }
 
+    [UnmanagedCallersOnly(EntryPoint = "qtl_tbf")]
+    public static int QtlTbf(double* source, double* output, int n, int period, double bandwidth, int length)
+    {
+        if (source == null || output == null) return StatusCodes.QTL_ERR_NULL_PTR;
+        if (n <= 0) return StatusCodes.QTL_ERR_INVALID_LENGTH;
+        try
+        {
+            var src = Src(source, n);
+            var dst = Dst(output, n);
+            Span<double> bpScratch = n <= 4096 ? stackalloc double[n] : new double[n];
+            Tbf.Batch(src, dst, bpScratch, period, bandwidth, length);
+            return StatusCodes.QTL_OK;
+        }
+        catch { return StatusCodes.QTL_ERR_INTERNAL; }
+    }
+
     [UnmanagedCallersOnly(EntryPoint = "qtl_spearman")]
     public static int QtlSpearman(double* seriesX, double* seriesY, double* output, int n, int period)
     {