Add support for S3-backed image storage

assets/nsfw/README.md

@@ -0,0 +1,17 @@
+# Bundled NSFW model
+
+`model.onnx` is the pretrained model distributed with
+[Fyko/nsfw v0.2.0](https://github.com/fyko/nsfw/releases/tag/v0.2.0), based on
+[GantMan/nsfw_model](https://github.com/GantMan/nsfw_model).
+
+Source: https://github.com/fyko/nsfw/releases/download/v0.2.0/model.onnx
+
+Size: 17,320,596 bytes (approximately 16.5 MiB).
+
+SHA-256: `0dca163d933af88e03fa0f9d233655857e9cc9f38bfd2bc28ba57c486d70feaf`.
+
+The application embeds these bytes using `include_bytes!` and initializes the model only
+when dashboard S3 uploads are configured and `NSFW_CHECK_ENABLED` is enabled (the default).
+Set `NSFW_CHECK_ENABLED=false` to skip model initialization and moderation.
+Keep this file in the source checkout and build
+context; it does not need to be installed separately alongside the compiled binary.