Initial publish: SamGeo3 multi-prompt segmentation lab.

Scripts, prompt JSON tiers, usage docs, and README. Input images
(data/) and segmentation outputs (output/) are gitignored.

.gitignore

@@ -0,0 +1,45 @@
+.venv/
+__pycache__/
+*.py[cod]
+*.egg-info/
+.ipynb_checkpoints/
+.DS_Store
+Thumbs.db
+
+# Local secrets / HF
+.env
+.hf_token
+
+# ---- Input / output data (publish code only) ----
+# Keep folder structure via .gitkeep; ignore all payloads.
+data/*
+!data/.gitkeep
+output/*
+!output/.gitkeep
+
+# Large model / geospatial / mask artifacts (anywhere)
+*.pt
+*.pth
+*.ckpt
+*.npy
+*.tif
+*.tiff
+*.jp2
+*.gpkg
+*.shp
+*.dbf
+*.shx
+*.prj
+*.las
+*.laz
+
+# Accidental root-level media dumps
+/*.jpg
+/*.jpeg
+/*.JPG
+/*.JPEG
+/*.png
+/*.PNG
+/*.webp
+/*.mp4
+/*.mov