Fix gin config loading + source filter, docs updates

- config_loader: add base_gin_files() to exclude dataset-specific
  pipeline_*.gin variants from default `python -m src.main` load
  (pipeline_uav_visloc.gin was overriding pipeline.gin)
- main.py: use base_gin_files() in the --gin override branch too
- pipeline.gin: source None (both DB + query) — was 'query',
  which silently dropped all DB satellite crops from discovery
- README/CLAUDE/docs: sync source default, tensor format spec

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

in/config_files/pipeline.gin

@@ -1,6 +1,6 @@
 # Pipeline configuration: what to process and where to save
-PipelineConfig.input_root = '/mnt/data1tb/cvgl_datasets/UAV-GeoLoc'
-PipelineConfig.output_root = '/mnt/data1tb/cvgl_datasets/World-UAV-aug'
+PipelineConfig.input_root = '/media/servml/SSD_2_2TB1/datasets/cvgl_datasets/UAV-GeoLoc/'
+PipelineConfig.output_root = '/media/servml/SSD_2_2TB1/datasets/cvgl_datasets/UAV-GeoLoc-aug/'
 PipelineConfig.stages = ['depth', 'edges', 'segmentation', 'chmv2']
 PipelineConfig.save_npy = False
 PipelineConfig.save_vis = True
@@ -10,5 +10,5 @@ PipelineConfig.cleanup_npy = False
 PipelineConfig.resume = True
 PipelineConfig.subset = None
 # Source filter: 'db' = satellite only, 'query' = drone/UAV only, None = both
-PipelineConfig.source = 'query' #'db'
+PipelineConfig.source = None  # None = both DB (satellite) + query (drone); 'db' or 'query' to restrict
 PipelineConfig.log_level = 'INFO'