add the loading screen

README.md

@@ -18,6 +18,8 @@ stateDiagram-v2
     [*] --> Main
 
     state "Main View<br>(timer + weight)" as Main
+    state "Menu<br>(carousel)" as Menu
+    state "Bluetooth Pairing<br>(waiting for connection)" as BTPairing
     state "Recipe Selection<br>(carousel)" as RecipeSelection
     state "Do Recipe<br>(step-by-step)" as DoRecipe
     state "Edit Recipe<br>(step list)" as EditRecipe
@@ -26,8 +28,14 @@ stateDiagram-v2
     state "Edit Step – Value Entry<br>(morse input)" as ValueEntry
     state "Edit Step – Goal Time Entry<br>(morse input)" as GoalTime
 
+    Main --> Menu : both long press
     Main --> RecipeSelection : right long press
 
+    Menu --> Main : left long press [back]
+    Menu --> BTPairing : right long press [BT Pair]
+
+    BTPairing --> Menu : left long press [cancel]
+
     RecipeSelection --> Main : left long press
     RecipeSelection --> DoRecipe : right long press [on recipe → run]
     RecipeSelection --> EditRecipe : both long press [on recipe → edit]<br>or right long press [on + → add]
@@ -48,4 +56,28 @@ stateDiagram-v2
     ValueEntry --> GoalTime : left long press [WEIGH_WITH_TIMER]
 
     GoalTime --> EditRecipe : left long press [save]<br>or left press [cancel]
-```
+```
+
+## Tools
+
+### `export_loading_frames.py`
+
+Renders the loading screen animation and exports every unique frame as both PNG files and a NumPy array.
+
+**Usage**
+```bash
+uv run export_loading_frames.py [--out-dir <directory>]
+```
+
+| Argument | Default | Description |
+|---|---|---|
+| `--out-dir` | `frames/` | Directory to write output files into |
+
+**Outputs**
+
+| File | Description |
+|---|---|
+| `frames/frame_XXXX.png` | One PNG per unique frame, zero-padded index |
+| `frames/frames.npy` | NumPy array of shape `(N, H, W)`, dtype `bool` |
+
+Consecutive duplicate frames are collapsed so only visually distinct frames are exported. The script prints the total number of frames rendered and the number of unique frames kept.