Clarify normalized annotation coordinates in dataset index

checksums.sha256

@@ -36,7 +36,7 @@ c7ac86359012295cbee32185c19c5b239728a6b4c91baf6f1f8cfbd48d1f4f81  annotations/wi
 cd857623b14b132ee11906cf9cf7df0ed778ae4861c97d571ce0bb2440600712  annotations/wipe-panel-corners/tracks.parquet
 b224ed12996f586db6fbf49b2f2fe58653de0745e128ed1158026ddcee8f9fbf  annotations/wipe-panel-corners/tracks_raw.parquet
 7cccb893b5f3a043c2bd96326ea107bd8b817eca089fcf1bce1375af0497e7b1  data/episodes.parquet
-fd9c841dfb8ec633673ff1c4da9ffe3be95e79eac2c0f819030911faebef9797  dataset.json
+ccab1aa6ab30241bf9650bc5792994d6f1c6e4fac93ca9898deaffbe14c1cbf7  dataset.json
 d276f5ee053b6e582e95881ab228cbc1a0281ee1936266a5b22952935d963cb2  episodes/brush-front-grille.json
 1e8a111cca296299bb47c465c1058e6b1953d32db92046ddc782f0d70e716943  episodes/brush-housing.json
 3787cf9ea4cfaf6ee2e3ff17a51eec9f09aa73db8e4be93d9d17040315c479f3  episodes/brush-panel-channels.json

dataset.json

@@ -6,7 +6,7 @@
   "release_status": "release",
   "license": "cc-by-4.0",
   "robot_actions": "absent",
-  "coordinate_frame": "2D displayed RGB pixels; no metric camera/world calibration",
+  "coordinate_frame": "2D displayed RGB image axes (+x right, +y down); hand x/y and object boxes use width/height-normalized coordinates; no metric camera/world calibration",
   "episodes": [
     {
       "capture_id": "remove-tape",