Declare proprietary licensing and enforce permissive-only dependencies

Continuum is intended to be sold, so every dependency has to permit
distribution in closed-source commercial software. Nothing recorded that
before: our own crates and npm packages carried no licence field at all,
which made `cargo deny` report them as `unlicensed` errors and left the
actual policy nowhere.

Crates now declare `LicenseRef-Proprietary` with `publish = false`.
That string is deliberately not a real SPDX identifier, so it must never
appear in a `deny.toml` allow list - a third-party crate claiming it
would be a genuine finding. npm packages use `"license": "UNLICENSED"`,
the equivalent convention there.

`deny.toml` holds the permissive-only allow list. The policy itself, the
audit, and the three categories cargo-deny cannot see (external
binaries, ML model weights, self-hosted servers) are documented in
continuum-common's docs/LICENSES.md.

packages/rust-types/Cargo.toml

@@ -2,6 +2,10 @@
 name = "continuum-rust-types"
 version = "0.1.0"
 edition = "2021"
+# Proprietary: deliberately not an SPDX id, so cargo-deny treats it as
+# first-party. See docs/LICENSES.md in continuum-common.
+license = "LicenseRef-Proprietary"
+publish = false
 
 [lib]
 name = "continuum_types"

packages/ts-types/package.json

@@ -1,5 +1,6 @@
 {
   "name": "@continuum/ts-types",
+  "license": "UNLICENSED",
   "version": "0.1.0",
   "private": true,
   "type": "module",