gen-cards: regenerate Use-it block

README.md

@@ -27,6 +27,47 @@ head (174 classes of *physical interactions* — put/lift/push/roll/cover/preten
 - **Speed**: ~150–180 ms per 16-frame clip on an M4 Max (GPU) — real-time video understanding.
 
 <!-- gen-cards:use-it begin id=vjepa2-vitl-ssv2 (managed by scripts/gen-cards — edit cards.json / QuickStart.swift, not this block) -->
+## Use it
+
+▶️ **Run it (source)** — the [ActionCamera runner](https://github.com/john-rocky/coreai-kit/tree/main/Examples/ActionCamera)
+(live camera action recognition, one app for every video model in the catalog):
+
+```bash
+git clone https://github.com/john-rocky/coreai-kit
+open coreai-kit/Examples/ActionCamera/ActionCamera.xcodeproj
+# → Run, then pick "V-JEPA 2 ViT-L (SSv2)" in the model picker
+
+# agents / headless (macOS):
+cd coreai-kit/Examples/ActionCamera
+swift run action-cli --model vjepa2-vitl-ssv2 --video sample.mp4
+```
+
+💻 **Build with it** — complete; the glue is kit API, copy-paste runs:
+
+```swift
+import CoreAIKitVision
+
+let recognizer = try await ActionRecognizer(catalog: "vjepa2-vitl-ssv2")
+let actions = try await recognizer.classify(videoAt: videoURL, topK: 3)
+// actions: ranked [Prediction] — .label ("Pushing [something] from left to right"),
+// .probability; 174 SSv2 classes, fully on-device
+```
+
+The take-home is [`Examples/ActionCamera/Sources/QuickStart.swift`](https://github.com/john-rocky/coreai-kit/blob/main/Examples/ActionCamera/Sources/QuickStart.swift)
+— this exact code as one typed function, no UI; the CLI is an argument shell over it, and
+the GUI classifies a rolling 16-frame clip from `CameraFeed`.
+Live camera? Keep the last 16 `CameraFeed` frames and call `classify(frames:)` — other
+frame counts are uniformly resampled to 16. The bundled `sample.mp4` is a synthetic
+clip (a hand pushing a block); point `--video` at real footage for real results.
+
+**Integration checklist**
+
+- SPM: `https://github.com/john-rocky/coreai-kit` → product **CoreAIKitVision**
+- Info.plist: `NSCameraUsageDescription` — only for the live camera; the snippet needs none
+- Entitlements: none needed
+- First run downloads the model — 0.7 GB (Mac) / 1.4 GB (iPhone) — then it loads from the
+  local cache (Application Support; progress via the `downloadProgress` callback)
+- Measure in Release — Debug is ~3× slower on per-token host work
 <!-- gen-cards:use-it end -->
 
 ## Files