Closes #826

With Claude.

D3.js DOM Manipulation Removal - Complete Migration (#826)

Summary

Successfully completed the removal of D3.js DOM manipulation from all 37 MMGIS frontend files, replacing with jQuery/vanilla JS while preserving D3 for specialized data visualization functions (charts, time formatting, coordinates).

Changes Made

Phase 4-8 Completion & Bug Fixes

Files Fixed (5):

1. UserInterfaceMobile_.js - Converted all active .style() calls to .css()
2. LegendTool.js - 171+ conversions across:
   - Header and container initialization
   - Image container rendering
   - Shape rendering (circle, square, rect, image, icon)
   - Gradient and scale rendering with tick marks
   - Units labels and positioning
   - Tooltip functionality
3. Viewer_.js - 76 conversions across all viewer modes (images, panoramas, PDFs, videos, GIFs, 3D models)
4. MeasureTool.js - Fixed 2 .style() calls causing runtime error (user-reported bug)
5. SitesTool.js - Fixed incorrect .append('div') pattern

Files Verified Clean (32):

• Phases 5-8: All tools, layers system, and advanced tools verified with 0 jQuery conversion bugs

Critical Bug Fixes

1. ToolController_.js - Separated Tool DOM Structure (src/essence/Basics/ToolController_/ToolController_.js)

• Issue: Icons were rendered as siblings instead of children of tool buttons
• Root Cause: D3's .append() returns the new child element, jQuery's .append() returns the parent
• Impact: Click handlers were attached to wrong element, causing interaction bugs
• Fix: Restructured to create elements first, then append in correct hierarchy

2. ScaleBar SVG Rendering (src/essence/Basics/Map_/Map_.js)

• Issue: ScaleBar not rendering - D3 couldn't manipulate SVG elements created by jQuery
• Root Cause: jQuery's $('') doesn't set proper XML namespace
• Fix: Changed to document.createElementNS('http://www.w3.org/2000/svg', 'svg')

3. Tooltip Rendering (src/essence/Tools/Legend/LegendTool.js)

• Issue: Custom tooltips instead of native browser tooltips
• Fix: Removed custom CSS that was overriding native title attribute rendering

D3 Retained (As Intended)

Full D3 Usage:

• ChemistryTool (3 files) - Full D3 charts and data visualization
• MetricsGraphics (external library) - Third-party dependency requires full D3

Selective D3 Functions:

• ScaleBar.js - d3.scaleLinear(), d3.axisBottom() for scale charts (with proper SVG manipulation)
• Time formatting (4 files) - d3.utcFormat() for UTC timestamps (LayerCapturer.js, TimeControl.js, IdentifierTool.js, ShadeTool.js)
• CursorInfo.js - d3.pointer() for mouse coordinates

Migration Pattern Documentation

Key D3 vs jQuery Differences:
// D3: Returns NEW child element
const child = parent.append('div')

// jQuery: Returns PARENT element
const stillParent = parent.append($('