76f6ba3706
Home Manager separates an installation from a daemon. This module put both under `services.hermes-agent`, and `installPackage` added a program to the PATH from a service module. `programs.hermes-agent` now installs the command line application and the desktop application. `services.hermes-agent` keeps the state, the configuration and the daemons, and stays the authority: the new module reads `hermesHome` and the backend address from it. A person can enable one without the other, which is a machine with an application and no gateway, or a headless gateway with no display. The desktop application needs this split to work correctly. A launcher that starts from the desktop menu reads no shell profile, thus the HERMES_HOME that `home.sessionVariables` exports reaches an interactive shell only. Home Manager writes `systemd.user.sessionVariables` to environment.d, and this module puts no HERMES_HOME there, because that file applies to each user unit. The application then opens ~/.hermes while the services use `hermesHome`, and the person sees no sessions and no keys. Thus the launcher carries the value itself, through a new `extraEnv` argument on the desktop package. The application also gets the Nix agent package, with HERMES_DESKTOP_HERMES. The usual distribution of the Electron application carries its own Hermes runtime and downloads more at the first start. `hermesDesktop` is a passthru of the agent and pins `finalAttrs.finalPackage`, so an override of `extraPythonPackages` or `extraDependencyGroups` reaches both. One machine thus has one runtime. `backend.sessionTokenFile` connects the application to the backend of the service. Without it the module runs `hermes serve` and the application starts a backend of its own, which gives two backends on one HERMES_HOME. The backend reads the file into HERMES_DASHBOARD_SESSION_TOKEN. The launcher reads the same file into HERMES_DESKTOP_REMOTE_TOKEN, beside a HERMES_DESKTOP_REMOTE_URL that names the address of the service. Measurements against a live `hermes serve` on loopback show why that shape is the correct one: - `_resolve_session_token()` reads HERMES_DASHBOARD_SESSION_TOKEN, and `_has_valid_session_token` accepts that value as a Bearer credential. A request without it gets 401, and a request with the wrong value gets 401. - The /api/ws socket accepts a query parameter only. A header gets 403, and `?token=` connects. Hermes Desktop builds exactly that URL, in `apps/desktop/electron/connection-config.ts`. Thus a test of the HTTP leg alone is a false positive. - `resolveDesktopRemoteRoute` throws when the URL is set and the token is not. Thus the two variables travel together or not at all. The token enters no Nix store path. `makeWrapper --set` and a systemd `Environment=` value both write a literal into the store, which all users can read. Thus each side reads the file at start time. The launcher does it through a new `extraRun` argument on the desktop package, and the backend through the launcher script that `backend.waitFor` already uses. launchd has no EnvironmentFile, so a script is the one shape that works on Linux and on Darwin. `backendArgv` gives the plain argv only when nothing must run before the backend. `services.hermes-agent.installPackage` is removed. It defaulted to true, so a person who never named it still got the command line. A silent removal thus gives them a machine with no `hermes` and no message. The module refuses a configuration that sets it, and the text names the exact replacement for the value they gave. Checks: - the launcher carries HERMES_HOME - the launcher reports HERMES_MANAGED only when the services own the configuration, because no activation writes a marker without them - the launcher pins the agent package that `programs.enable` installs - the launcher names the backend of the service, and gives a token beside the URL - the backend reads the session token - each side reads the file at start time, and the token is no `--set` value - `programs.enable` alone starts no service - `installPackage` is refused, with a message that names the replacement, and its absence evaluates Each check reads the wrapper of the real package, and not an option value. Each one was tested with a mutation that breaks the behavior it asserts.