Service restart, gateway key and init consent claims the docs corrected are still in the tool, app and dashboard text #339

The docs accuracy pass (#330) corrected these claims in the docs. The same claims are still shown to users by the tool, the desktop app and the dashboard, and appear in two code comments. #330 changes only docs, so they are filed here. Line numbers are from main at 1c35921.

1. "Restarts it if it fails" is shown on every platform. The Windows sign-in entry is a Run value, so nothing restarts the router when it exits. docs/host.md's table says "not automatically", and the docs now say so wherever this claim appears.

• src/SemanticRouter.Hosting/ServiceCommand.cs:97: printed by service install.
• src/SemanticRouter.Desktop/WelcomeWindow.cs:39 and SettingsWindow.cs:59: the help text for "Keep the router running in the background".
• src/SemanticRouter.AspNetCore/Dashboard/wwwroot/js/service.js:229 (install confirmation) and :328 (Background service card).
• src/SemanticRouter.Desktop/RouterService.cs:7: doc comment.

2. The dashboard's Connect clients snippet says the gateway key is ignored. wwwroot/js/config.js:447 has # any value: the router ignores it and never forwards it. GatewayAuthentication.Admit (GatewayGuard.cs:95-132) reads that token as a gateway key. Any value is accepted only from this machine, and only while RequireGatewayKeyForLocalClients is off. The README and docs/clients.md now say: "any value from this machine; with gateway keys set, send yours (required from other machines). Never forwarded".

3. init --help says it asks about each subscription CLI. src/SemanticRouter.Host/Program.cs:70 reads "It asks before enabling each subscription CLI". In fact copilot is never asked about: it is added disabled unless --enable-cli names it (InitCommand.cs:294-300, :335-340).

4. A code comment puts the Windows service log in the wrong directory. src/SemanticRouter.Hosting/ServicePlatforms.cs:406 says the log is in the configuration directory. It is in the local data directory (ServiceCommand.cs:387).

Done when: these strings match docs/host.md#run-it-in-the-background and docs/clients.md, and any test that asserts the old text is updated.