Initial commit: video effects processing system

Add S-expression based video effects pipeline with modular effect
definitions, constructs, and recipe files.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

effects/sharpen.py

@@ -0,0 +1,63 @@
+# /// script
+# requires-python = ">=3.10"
+# dependencies = ["numpy", "opencv-python"]
+# ///
+"""
+@effect sharpen
+@version 1.0.0
+@author artdag
+
+@description
+Sharpening effect using unsharp mask technique. Enhances edges and detail.
+Great for making footage pop on beats.
+
+@param amount float
+  @range 0 5
+  @default 1.0
+  Sharpening intensity. 0 = no change, 1 = normal, 2+ = aggressive.
+
+@param radius float
+  @range 0 10
+  @default 1
+  Radius of sharpening (affects edge thickness).
+
+@example
+  (effect sharpen :amount 1.5)
+
+@example
+  ;; Sharpen on beats
+  (effect sharpen :amount (bind bass :range [0.5 2.0]))
+"""
+
+import numpy as np
+import cv2
+
+
+def process_frame(frame: np.ndarray, params: dict, state: dict) -> tuple:
+    """
+    Apply sharpening to a video frame.
+
+    Args:
+        frame: Input frame as numpy array (H, W, 3) RGB uint8
+        params: Effect parameters
+            - amount: sharpening intensity (default 1.0)
+            - radius: edge radius (default 1)
+        state: Persistent state dict (unused)
+
+    Returns:
+        Tuple of (processed_frame, new_state)
+    """
+    amount = params.get("amount", 1.0)
+    radius = params.get("radius", 1)
+
+    if amount <= 0:
+        return frame, state
+
+    # Create blurred version
+    ksize = max(1, int(radius)) * 2 + 1
+    blurred = cv2.GaussianBlur(frame, (ksize, ksize), 0)
+
+    # Unsharp mask: original + amount * (original - blurred)
+    result = frame.astype(np.float32) + amount * (frame.astype(np.float32) - blurred.astype(np.float32))
+
+    return np.clip(result, 0, 255).astype(np.uint8), state