Make the no-op Windows `set_launch_command` real. New `windows/interactive.rs`
`spawn_in_active_session` (WTSGetActiveConsoleSessionId → WTSQueryUserToken →
CreateProcessAsUserW(winsta0\default) under the LOGGED-IN USER token, factored from
the wgc_relay primitive) + `library::launch_title` resolving a store-qualified id to
a concrete process via `windows_launch_for` (steam_appid → Steam.exe/explorer.exe
steam:// URI; command → cmd.exe /c). Threaded as `SessionContext.launch` into both
native data-plane paths (`virtual_stream`, `virtual_stream_relay`) and fired after
capture is live so the title renders onto the captured desktop and grabs foreground.
Security invariant intact: the client sends only the store-qualified id; the host
resolves the recipe from its own library and the URI/flags are handed to a concrete
EXE as plain args (never cmd /c of a client string). Linux unchanged (gamescope
nesting via the handshake PUNKTFUNK_GAMESCOPE_APP path).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
c87ca577a3