Implement background exclusion and refactor folder structure

- Added configurable background exclusion (#1f2937) with tolerance
- Implemented alpha thresholding (>= 128) to eliminate edge artifacts
- Refactored folder structure into analyses/[slug]/images, settings, and results
- Updated pattern puller to skip existing images and handle network errors
- Updated .gitignore and automated tests for path integrity

app/logic/__init__.py

@@ -6,6 +6,8 @@ from .constants import (
     IMAGES_DIR,
     LANGUAGE,
     OVERLAY_COLOR,
+    EXCLUDE_BG_COLOR,
+    EXCLUDE_BG_TOLERANCE,
     PREVIEW_MAX_SIZE,
     RESET_EXCLUSIONS_ON_IMAGE_CHANGE,
     SUPPORTED_IMAGE_EXTENSIONS,
@@ -17,6 +19,8 @@ __all__ = [
     "IMAGES_DIR",
     "LANGUAGE",
     "OVERLAY_COLOR",
+    "EXCLUDE_BG_COLOR",
+    "EXCLUDE_BG_TOLERANCE",
     "PREVIEW_MAX_SIZE",
     "RESET_EXCLUSIONS_ON_IMAGE_CHANGE",
     "SUPPORTED_IMAGE_EXTENSIONS",

app/logic/constants.py

@@ -94,7 +94,12 @@ def _extract_language(data: dict[str, Any]) -> str:
 
 _CONFIG_DATA = _load_config_data()
 
-_OPTION_DEFAULTS = {"reset_exclusions_on_image_change": False, "overlay_color": "#ff0000"}
+_OPTION_DEFAULTS = {
+    "reset_exclusions_on_image_change": False,
+    "overlay_color": "#ff0000",
+    "exclude_bg_color": "#1f2937",
+    "exclude_bg_tolerance": 5,
+}
 
 
 def _extract_options(data: dict[str, Any]) -> dict[str, Any]:
@@ -108,6 +113,12 @@ def _extract_options(data: dict[str, Any]) -> dict[str, Any]:
     color = section.get("overlay_color")
     if isinstance(color, str) and color.startswith("#") and len(color) in (7, 9):
         result["overlay_color"] = color
+    exclude_bg = section.get("exclude_bg_color")
+    if isinstance(exclude_bg, str) and exclude_bg.startswith("#") and len(exclude_bg) in (7, 9):
+        result["exclude_bg_color"] = exclude_bg
+    tolerance = section.get("exclude_bg_tolerance")
+    if isinstance(tolerance, int):
+        result["exclude_bg_tolerance"] = max(0, min(255, tolerance))
     return result
 
 
@@ -116,3 +127,5 @@ LANGUAGE = _extract_language(_CONFIG_DATA)
 OPTIONS = {**_OPTION_DEFAULTS, **_extract_options(_CONFIG_DATA)}
 RESET_EXCLUSIONS_ON_IMAGE_CHANGE = OPTIONS["reset_exclusions_on_image_change"]
 OVERLAY_COLOR = OPTIONS["overlay_color"]
+EXCLUDE_BG_COLOR = OPTIONS["exclude_bg_color"]
+EXCLUDE_BG_TOLERANCE = OPTIONS["exclude_bg_tolerance"]