Add Cargo workspace, crate skeletons and the gate

Implemented-By: Laguna S 2.1 (OpenCode)

deny.toml

@@ -0,0 +1,25 @@
+# cargo-deny configuration. `make gate` runs bans, licenses and sources offline.
+# `make audit` runs advisories, which fetches the RustSec database.
+
+[graph]
+all-features = true
+
+[licenses]
+allow = ["MIT", "Apache-2.0", "Unicode-3.0"]
+confidence-threshold = 0.9
+
+[licenses.private]
+ignore = true
+
+[bans]
+multiple-versions = "deny"
+wildcards = "deny"
+allow-wildcard-paths = true
+
+[sources]
+unknown-registry = "deny"
+unknown-git = "deny"
+allow-registry = ["https://github.com/rust-lang/crates.io-index"]
+
+[advisories]
+yanked = "deny"