feat(extension): enhance Chrome Extension popup UI

[tmimmanuel]

Summary

• Redesigned the Chrome extension popup with a modern dark/light theme UI
• Added dark mode as default with a toggle button to switch to light theme (persisted in storage)
• Replaced flat styling with glassmorphism cards, gradient accent buttons, and layered shadows
• Added inline SVG icons (Lucide-style) for status rows and action buttons
• Added animated status badge with pulsing dot for connected state and shimmer effect during sync
• Improved spacing, typography (Inter font), and overall readability across all elements
• Enhanced borders and shadows on cards, inputs, and buttons for better visual depth

Test plan

• Load the extension in Chrome (chrome://extensions → Load unpacked)
• Verify dark theme renders correctly on popup open
• Click the sun/moon toggle to switch to light theme — verify all elements adapt
• Close and reopen popup — verify theme preference is persisted
• Verify status badge shows correct state (Disconnected / Connected / Error)
• Test Sync and Refresh buttons — verify shimmer animation and loading text
• Verify Service URL input focus glow and save functionality
• Test Disconnect button clears state and resets UI

Closes #21

Prev UI:

Updated UI:

[Chkhikvadze]

Closing as duplicate of #34 (Chrome Extension cookie bridge). This PR implements the same Chrome extension feature as #34, but had incorrect service port (8000 vs correct 8899) and was missing JS unit tests. PR #34 passed 304/304 tests and has been merged to main. Thank you for the contribution.

[tmimmanuel]

@Chkhikvadze Could you please reopen my PR?
I will add some inputs to improve the Chrome Extension UI of #34

[tmimmanuel]

@Chkhikvadze I updated the UI, please review.