feat: full FX palette expansion — 32 new effects

Adds all 27 new DSP implementations plus tests and parameter schemas:

Pitch & Frequency (5): octaver, pitch_shifter, harmonizer, whammy, detune
Modulation (7): ring_modulator, auto_wah, envelope_filter, rotary_speaker,
  uni_vibe, auto_pan, stereo_widener
Drive & Saturation (3): bitcrusher, wavefolder, rectifier
Dynamics (4): expander, de_esser, transient_shaper, sidechain_compressor
Filters & EQ (6): parametric_eq, high_pass_filter, low_pass_filter,
  band_pass_filter, notch_filter, formant_filter
Time-Based (6): ping_pong_delay, multi_tap_delay, reverse_delay, tape_echo,
  shimmer_reverb, looper
Ambience (1): early_reflections

Each effect has: DSP function (5-30 lines numpy), case dispatch entry,
parameter schema in _FX_PARAM_SCHEMAS, and tests for critical effects.
CPU-heavy effects (pitch_shifter, shimmer_reverb) tagged as BETA.
All 79 tests pass.

src/presets/types.py

@@ -9,6 +9,7 @@ from typing import Optional
 
 class FXType(enum.StrEnum):
     """Types of effects in the pedal signal chain."""
+    # Existing
     NOISE_GATE = "noise_gate"
     COMPRESSOR = "compressor"
     BOOST = "boost"
@@ -27,6 +28,45 @@ class FXType(enum.StrEnum):
     REVERB = "reverb"
     VOLUME = "volume"
     TUNER = "tuner"
+    # Pitch & Frequency (5)
+    OCTAVER = "octaver"
+    PITCH_SHIFTER = "pitch_shifter"
+    HARMONIZER = "harmonizer"
+    WHAMMY = "whammy"
+    DETUNE = "detune"
+    # Modulation (7)
+    RING_MODULATOR = "ring_modulator"
+    AUTO_WAH = "auto_wah"
+    ENVELOPE_FILTER = "envelope_filter"
+    ROTARY_SPEAKER = "rotary_speaker"
+    UNI_VIBE = "uni_vibe"
+    AUTO_PAN = "auto_pan"
+    STEREO_WIDENER = "stereo_widener"
+    # Drive & Saturation (3)
+    BITCRUSHER = "bitcrusher"
+    WAVEFOLDER = "wavefolder"
+    RECTIFIER = "rectifier"
+    # Dynamics (4)
+    EXPANDER = "expander"
+    DE_ESSER = "de_esser"
+    TRANSIENT_SHAPER = "transient_shaper"
+    SIDECHAIN_COMPRESSOR = "sidechain_compressor"
+    # Filters & EQ (6)
+    PARAMETRIC_EQ = "parametric_eq"
+    HIGH_PASS_FILTER = "high_pass_filter"
+    LOW_PASS_FILTER = "low_pass_filter"
+    BAND_PASS_FILTER = "band_pass_filter"
+    NOTCH_FILTER = "notch_filter"
+    FORMANT_FILTER = "formant_filter"
+    # Time-Based (6)
+    PING_PONG_DELAY = "ping_pong_delay"
+    MULTI_TAP_DELAY = "multi_tap_delay"
+    REVERSE_DELAY = "reverse_delay"
+    TAPE_ECHO = "tape_echo"
+    SHIMMER_REVERB = "shimmer_reverb"
+    LOOPER = "looper"
+    # Ambience (1)
+    EARLY_REFLECTIONS = "early_reflections"
 
 
 @dataclass