Activation sent `machine_uid::get()` as is: /etc/machine-id on Linux,
MachineGuid on Windows. machine-id(5) calls that id confidential and asks
applications to send a keyed hash under a fixed, application-specific key
instead. The license server stores what it receives next to the license
email and the host name, lists it back and signs it into the activation
token.
- derive_machine_id: HMAC-SHA256 under a frozen key, 64 lowercase hex
characters, pinned by two reference vectors. An empty OS id is refused,
never hashed.
- Activation sends the derived identifier and requires the issued token to
carry it. Nothing else originates a machine identifier.
- A machine activated before this change stays activated: a valid token
whose claim is the raw id of this machine still reads "Activated" (D1).
- The machine list flags `is_this_machine` in Rust, for a row under either
identifier (D3). `ActivationStatus` no longer carries an identifier and
the unused `get_machine_id` command is removed: no command hands the OS
id to the webview any more.
- After a deactivation the local token is dropped when it stood for the
freed slot: any row of this machine takes it, except the old raw row
while the token stands for the derived one.
- ADR 0020 records the derivation, the transition and the condition for
removing the raw-id compatibility.
Behaviour changes beyond the issue text: the machine list and a
deactivation no longer fail on an unreadable OS id (best effort), the
activation status then reads "not activated" instead of failing, and the
unused `store_activation_token` command refuses a token issued for the
raw id.
No new dependency (hmac and sha2 were already declared); Cargo.lock is
untouched. Rust 151 -> 168 tests, vitest 1311 -> 1314.
Refs #350
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>