Refactor visualization layout to single-column design

[benbel]

Summary

This PR significantly refactors the visualization layout from a multi-column grid to a single-column design, removing header/footer sections and simplifying the overall UI while improving interactivity.

Key Changes

Layout & Structure

• Changed charts grid from multi-column responsive layout to single-column flex layout
• Removed header section with title and subtitle
• Removed footer with metadata and links
• Removed statistics cards display
• Changed container max-width from 1400px to 100%

Chart Rendering

• Increased chart width from 280px to 800px to utilize full container width
• Reduced chart height from 180px to 120px for more compact display
• Significantly reduced margins (from 10-40px to 5px) for better space efficiency
• Removed chart subtitles showing modification count
• Simplified chart header to only show title

Interactivity Improvements

• Made controls bar sticky (position: sticky, top: 0, z-index: 100)
• Added tooltip pinning functionality - users can click points to pin tooltips
• Changed tooltip pointer-events from none to auto for better interaction
• Added click handler to close pinned tooltips when clicking elsewhere
• Improved point hover states with visual feedback

Scale Management

• Renamed display mode from "brut/net" to "per-code/common" scale modes
• Removed net mode (solde) calculation entirely
• Simplified to only show additions and deletions separately
• Added ability to toggle between per-code and common scales
• Sorted codes by modification score (descending) for better visibility

Code Simplification

• Removed axis rendering (no visible axes in new compact design)
• Removed net mode rendering logic
• Removed stats display functions
• Simplified tooltip content and links
• Removed legend dynamic updates for mode switching

Responsive Design

• Updated mobile breakpoint to adjust padding and font sizes
• Made controls flex-direction column on mobile
• Reduced chart padding on mobile devices

Implementation Details

• Charts now use per-code scales by default, with option to switch to common scales
• Tooltip pinning uses a global tooltipPinned flag to manage state
• Codes are sorted by total modification score for better prioritization
• Removed all axis-related CSS classes and rendering code
• Simplified data transformation by removing net mode calculations