Redesign NoCodeComments as a terminal-style developer tool

[Aaqibhafeezkhan]

Summary

• redesign the interface around a dense terminal / hacker aesthetic
• add dark and paper-terminal light themes with localStorage persistence
• add terminal wordmark, CLI-style theme toggle, language selector, and strip action
• add sharp two-pane editor layout with line-number gutters and pane tabs
• add comments removed, bytes saved, and lines removed stats
• add processing spinner, sweep animation, error state, success flash, keyboard shortcuts, and reduced-motion handling
• keep test snippets accessible from the app
• use the requested JetBrains Mono font stack and exact theme color systems

Validation

• based directly on current main
• one feature commit
• ready for review, not a draft
• no code comments added to generated HTML, CSS, or JavaScript