docs(rust/face-recognition): describe benchmarking endpoints without CLI examples

These are development tools, not user-facing features. No need to show CLI commands
that produce confusing output (Err on empty DB, noisy logs from old deployments).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: marc0olo

rust/face-recognition/README.md

@@ -4,11 +4,7 @@ This example demonstrates running face detection and face recognition inside an
 
 The example consists of two canisters:
 
-- **backend** — embeds the Tract ONNX inference engine. Exposes endpoints for uploading ONNX model files in chunks, loading them into memory, detecting faces, computing face embeddings, and recognizing people. Also exposes `run_detection` and `run_recognition` which run the models against a built-in test image and log the IC instruction count to the canister log — useful for smoke-testing and capacity planning:
-
-  ```bash
-  icp canister call --query backend run_detection '()'
-  ```
+- **backend** — embeds the Tract ONNX inference engine. Exposes endpoints for uploading ONNX model files in chunks, loading them into memory, detecting faces, computing face embeddings, and recognizing people. Also includes `run_detection` and `run_recognition` endpoints that run the models against a built-in test image and log the instruction count — useful during development for capacity planning.
 - **frontend** — serves the web UI (HTML/JS/CSS).
 
 ## Models