feat(clients/windows): single-window handoff, shared settings store, console-UI surfacing

UX polish batch 1 (clients/windows/ui-polish-plan.md, workstreams W0/A1/B/C/E):

- W0: the shell's duplicated trust/settings structs are gone — src/trust.rs
  re-exports pf-client-core's, so the shell and the spawned session binary share
  ONE Settings shape over client-windows-settings.json. Fixes real bugs: the
  shell's saves no longer drop session-side fields; the stats-overlay toggle
  (show_hud -> show_stats, serde alias migrates old files) and the forwarded-
  controller pick now actually reach the spawned session. The "Streaming engine"
  Settings combo is gone (PUNKTFUNK_BUILTIN_STREAM=1 stays as the dev A/B knob).

- Forwarded-controller pinning by stable key (vid:pid:name, pf-client-core's
  format): persisted as forward_pad, applied by the shell's own service at
  startup AND by the session binary in session_params (both OSes — the session
  never applied the pin before).

- A1 single window: the shell hides itself when the spawned session window
  presents its first frame ({"ready":true}) and restores + foregrounds on the
  child's exit — exactly one visible Punktfunk window at any time. Restore runs
  before the request-access cancel gate so a Ready/Cancel race can't strand the
  shell hidden.

- C console UI: punktfunk-session --browse gains --json-status (ready when the
  library window presents; error line on a failed start), and the shell
  surfaces it — "Open console UI" on paired hosts' menus, plus a controller-
  detected hint card targeting the most recent paired host (x64 only; aarch64
  ships no skia ui feature). Browse spawns hide/restore the shell like streams.

- B responsive: minimum window size (420x360); the hosts header collapses to
  icon-only buttons below 700 px; the session status card shrinks instead of
  clipping (max_width); busy pages, help actions, licenses and long labels wrap.

- E polish: session exe gets the app icon (winresource + WM_SETICON via the new
  pf-presenter win32.rs); both exes share an explicit AppUserModelID on
  unpackaged runs (packaged identity wins) so the windows group as one taskbar
  app across the visibility handoff; "Start streams fullscreen" toggle passes
  --fullscreen (GTK parity); connects stamp KnownHost::last_used; the connect
  target is stashed for every route so "Connecting to X" always names the host.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/session/build.rs

@@ -0,0 +1,19 @@
+//! Embed the Windows version-info + icon resources into `punktfunk-session.exe`. The
+//! icon drives Explorer, and `pf-presenter`'s `win32::stamp_window_icon` loads it by
+//! ordinal 1 onto the SDL window's title bar / taskbar / Alt-Tab (SDL's own window-class
+//! icon is the generic default).
+
+fn main() {
+    // cfg(windows) is the HOST (skips Linux/macOS builds of this cross-platform binary);
+    // CARGO_CFG_WINDOWS is the TARGET (x64 and cross-compiled ARM64 both pass).
+    #[cfg(windows)]
+    if std::env::var_os("CARGO_CFG_WINDOWS").is_some() {
+        let icon = "../../packaging/windows/branding/punktfunk.ico";
+        println!("cargo:rerun-if-changed={icon}");
+        winresource::WindowsResource::new()
+            // Ordinal 1 — pf-presenter's win32.rs loads it by this id for WM_SETICON.
+            .set_icon_with_id(icon, "1")
+            .compile()
+            .expect("embed windows icon resource");
+    }
+}