feat(sync): Windows machines work as sync remotes

Remote temp dirs are now created and removed by the remote SubMiner
itself (sync --make-temp / --remove-temp, validated against its own
tmpdir) instead of mktemp/rm, and the flow detects the remote shell
(POSIX, cmd, PowerShell) to pick quoting and SubMiner install-location
candidates - %LOCALAPPDATA% app install, launcher shim, or PATH - with
no POSIX PATH prefix on Windows. Remote temp paths are normalized to
forward slashes for scp and the CLI. Verified end-to-end against a
throwaway sshd with the app binary as the resolved remote command.

launcher/config/args-normalizer.ts

@@ -209,6 +209,8 @@ export function createDefaultArgs(
     syncForce: false,
     syncJson: false,
     syncCheck: false,
+    syncMakeTemp: false,
+    syncRemoveTempPath: '',
     syncUi: false,
     logLevel: loggingConfig.level ?? 'warn',
     logRotation: loggingConfig.rotation ?? 7,
@@ -286,6 +288,8 @@ export function applyInvocationsToArgs(parsed: Args, invocations: CliInvocations
     parsed.syncForce = invocations.syncForce;
     parsed.syncJson = invocations.syncJson;
     parsed.syncCheck = invocations.syncCheck;
+    parsed.syncMakeTemp = invocations.syncMakeTemp;
+    parsed.syncRemoveTempPath = invocations.syncRemoveTempPath ?? '';
     if (invocations.syncLogLevel) parsed.logLevel = parseLogLevel(invocations.syncLogLevel);
   }
   if (invocations.syncUiTriggered) {