[SeanShaffer88]

The dark theme moves from near-black to charcoal, and the house accent from bright red to crimson, matching the other projects.

• Core ThemeTokens: dark surfaces are now a charcoal ramp (#232323 window, #2B2B2B panels, #333333 raised, #404040 borders); the panel/chip hairlines carry the crimson accent itself; the chip plate follows the window surface. Text tiers, the red-gray selection, and the green readouts are unchanged — every contrast assertion still passes.
• AccentPalette: the default preset is now crimson #DC143C, presented as "Crimson" in Settings. The preset id stays "Red" internally so saved choices resolve to the same slot (now crimson); custom colours are untouched. The light theme's accent is the derived crimson #9B0E2A.
• App.xaml dictionaries updated to match (drift-guarded); text on the accent flips from black to white (white holds about 7:1 on crimson, black about 3:1).

Local gate green; Windows CI is the App build check. Runtime look Unverified until seen on a real machine.