core: route view_image through a sandbox-backed fs helper

codex-rs/fs-ops/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "codex-fs-ops"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[lib]
+name = "codex_fs_ops"
+path = "src/lib.rs"
+
+[lints]
+workspace = true
+
+[dependencies]
+anyhow = { workspace = true }
+base64 = { workspace = true }
+serde = { workspace = true, features = ["derive"] }
+serde_json = { workspace = true }
+
+[dev-dependencies]
+pretty_assertions = { workspace = true }
+tempfile = { workspace = true }