Initial scaffold: capture + vision modules with detect CLI

- capture/: frame sampling at configurable fps, ffmpeg audio extraction (WAV, whisper-ready)
- vision/: changed-pixel motion scoring, stable/moving segmentation, contour + perspective document detection, Laplacian sharpness scoring, optional CLAHE enhancement
- pipeline: two-pass detect (motion timeline, then best-frame crop per stable window) writing crops, debug frames, report.json, and motion_scores.csv
- CLI: probe / detect / extract-audio subcommands
- config.yaml with tunable thresholds; placeholder packages for events, transcribe, ocr, naming, pdf, review_cli
- synthetic sample video generator + 16 unit tests

config.yaml

@@ -0,0 +1,44 @@
+# PaperPod tunable thresholds. All values here override the built-in defaults
+# in paperpod/config.py; delete a key to fall back to the default.
+
+capture:
+  # Frames per second to sample from the source video for analysis.
+  sample_fps: 8
+  # Frames are downscaled to this width for motion analysis (full resolution
+  # is still used for the final document crops).
+  processing_width: 960
+
+audio:
+  # WAV sample rate for the extracted audio track (16 kHz mono = whisper-ready).
+  sample_rate: 16000
+
+motion:
+  # Gaussian blur kernel applied before frame differencing (odd number).
+  blur_ksize: 21
+  # A pixel counts as "changed" if its gray level moved by more than this (0-255).
+  pixel_threshold: 12
+  # Fraction of changed pixels (0.0-1.0) above which a frame counts as "moving".
+  # Raise if sensor noise triggers false motion; lower if small gestures
+  # (page flips) are being missed.
+  threshold: 0.02
+  # A stable stretch must last at least this long (seconds) to count as a window.
+  stable_min_duration_s: 1.0
+
+document:
+  # Contours smaller than this fraction of the frame area are ignored.
+  min_area_ratio: 0.04
+  # Canny edge detection thresholds.
+  canny_low: 50
+  canny_high: 150
+  # Apply contrast enhancement (CLAHE) to crops for OCR-readiness.
+  enhance: false
+
+speech:
+  # Window around a capture event in which to look for a spoken description.
+  window_before_s: 3.0
+  window_after_s: 5.0
+
+output:
+  dir: ./output
+  # Paperless-ngx consume directory (module 7, not wired up yet).
+  consume_dir: null