Keep button hover blue, and always use the dark look

[maralcbr]

Summary

Primary button hover was Try Omarchy's pale cyan, which reads as green. It now stays in the accent's blue, and the installer is always dark.

 primary button
-  hover    #B4F9F8  (pale cyan)
-  pressed  #7DCFFF  (cyan)
+  hover    #9AB8FA  (lighter accent blue)
+  pressed  #6690EC  (deeper accent blue)
 secondary button
-  hover text #B4F9F8
+  hover text #9AB8FA

 InstallerApplicationDelegate.applicationWillFinishLaunching
+  NSApp.appearance = .darkAqua      # windows, sheets, alerts, menus
 OmarchyTheme
-  dynamic(light:dark:) palette
+  fixed Tokyo Night (dark) palette
-OmarchyWordmark.lightRowColors
-SimulationDashboard "Dark mode" toggle

Evidence

• Before: hovering Continue fills it pale cyan; launching under macOS Light gives the light palette.
  After: hover is a lighter blue; launching with NSRequiresAquaSystemAppearance forced on still draws the dark window (checked in the debug simulator).
• Label contrast on the new fills: hover 8.6:1, pressed 5.5:1, secondary hover text on card 7.4:1.
• swift build (debug and release), strict swift-format lint, swift test: 677 tests, 0 failures.

Merge Danger

Door: two-way

Colour tokens and one appearance call; revert restores the light palette.

Blast Radius: appearance

People on macOS Light now get the dark installer. That is the intent, from install feedback.