feat(ux): wizard handoff note, daemon restart reminder, settings polish (code)

The code changes intended with the settings_window removal in a90aa29 (a bad
git-add pathspec aborted staging them there, leaving that commit with only the
file deletions and CMakeLists still referencing them):
- First-run handoff info toast at the completion point.
- Daemon-updater "restart pending" reminder (Settings → Daemon Binary) + the
  Done screen's warning-level "restart required" headline.
- Debug restart-note raised to a readable color with the restart prompt beneath
  it; DEBUG OPTIONS header shows a lock + explanatory caption (auth gate
  unchanged); a few hardcoded literals → material tokens / dpiScale.
- Drop the legacy settings_window from the build (CMakeLists + the dev-only
  references) to match the file deletions.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app_sweep.cpp

@@ -570,8 +570,6 @@ void App::buildSweepCatalog()
         [](App& a) { ui::ContactsSweepCloseDialog(); restoreSweepContacts(a); });
     add("modal-about", ui::NavPage::Overview,
         [](App& a) { a.show_about_ = true; }, [](App& a) { a.show_about_ = false; });
-    add("modal-settings", ui::NavPage::Settings,
-        [](App& a) { a.show_settings_ = true; }, [](App& a) { a.show_settings_ = false; });
 
     // Seed-backup: pre-set fetch + a demo phrase so it renders the word grid without any RPC.
     add("modal-seed-backup", ui::NavPage::Overview,