feat: scaffold Rust ML service crate

Create Rust crate skeleton with Cargo.toml, main.rs, and config.rs.
Includes package metadata, dependencies (anyhow, axum, image, ndarray,
ort, serde, tokio, tower, tracing), and config module with LABELS
constants, SERVICE_NAME, SERVICE_VERSION, DEFAULT_INPUT_SIZE, and
resolve_model_path function. Config tests verify label order, relative
path resolution, and absolute path preservation.

Also includes approved spec and implementation plan documents.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/ml-service/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "zeavis-ml-service"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0"
+axum = { version = "0.7", features = ["multipart"] }
+image = "0.25"
+ndarray = "0.15"
+ort = "2.0.0-rc.10"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+tokio = { version = "1.0", features = ["macros", "rt-multi-thread", "net"] }
+tower = "0.5"
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+
+[dev-dependencies]
+temp-env = "0.3"