feat(dark-mode): add force dark mode

[moonrailgun]

Background

Dao needs a user-facing control for applying Chromium Auto Dark Mode to websites when the system appearance is already dark, plus a corresponding product highlight on the website.

Changes

• Adds a persisted dao.force_dark_mode_enabled profile preference and helpers to determine availability, effective state, and web preference application.
• Integrates force dark mode into Chromium web preferences through a chrome_content_browser_client patch, including preference refresh after navigation.
• Adds a Control Center utility button for Force Dark Mode, with localized labels/tooltips, disabled behavior in light system mode, selected styling, and a moon icon.
• Moves the Share action into the Control Center More menu and keeps Little Dao site center free of the Force Dark Mode control.
• Highlights Force Dark Mode on the website feature grid and adds the moon icon to the website icon set.

Testing

Patch includes browser tests for force dark mode defaults, Control Center placement/toggling, More menu share action, and Little Dao exclusion. Patch also adds a Vitest coverage check for the homepage Force Dark Mode feature highlight.

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Review details

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 4ac90e80-4bca-45e9-949f-c367fcd0d2e9

📥 Commits

Reviewing files that changed from the base of the PR and between 3f42a0c and 274d224.

📒 Files selected for processing (17)

• src/dao/browser/dao_pref_names.cc
• src/dao/browser/dao_pref_names.h
• src/dao/browser/strings/dao_strings.grd
• src/dao/browser/ui/views/dao_browser_browsertest.cc
• src/dao/browser/ui/views/dao_control_center_more_menu.cc
• src/dao/browser/ui/views/dao_control_center_more_menu.h
• src/dao/browser/ui/views/dao_control_center_popup.cc
• src/dao/browser/ui/views/dao_control_center_popup.h
• src/dao/browser/ui/views/dao_control_center_utility_section.cc
• src/dao/browser/ui/views/dao_control_center_utility_section.h
• src/dao/browser/ui/views/dao_lucide_icons.cc
• src/dao/browser/ui/views/dao_lucide_icons.h
• src/patches/chrome/browser/chrome_content_browser_client_force_dark_mode.cc.patch
• website/components/FeatureGrid.module.css
• website/components/FeatureGrid.tsx
• website/components/ui/LucideIcon.tsx
• website/lib/__tests__/homepage-features.test.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch moonrailgun/force-dark-mode

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