feat(docs): update tool icons, navigation sidebar, and documentation skill rules

[kentemman-gmd]

Summary

This PR updates the GEMMA QGIS plugin UI icons and VitePress documentation to sync newly added gmd_scripts processing tools, improve dual-theme (Dark/Light mode) icon contrast, fix redundant horizontal section dividers, and enforce processing Algorithm ID documentation standards.

Problem / Rationale

• Navigation & Card Gaps: Newly added processing tools (Scan Geometry Errors, Repair Polygon Geometries, and Check and Update) were missing from the VitePress navigation dropdown, sidebar tree, and home index cards.
• Menu Icon Sharing & Visibility: The Updating of Boundaries and Others submenus shared generic packager.svg and low-contrast purple icons (#8E44AD) that were difficult to see in QGIS Dark Theme.
• Redundant Dividers: Explicit --- dividers placed above ## headings rendered as double horizontal lines in VitePress.
• Missing Algorithm IDs: Several tool guide pages lacked explicit Algorithm ID references under their ## Access sections.

Key Changes

1. QGIS Plugin UI & Dedicated SVG Icons (gmd_pipeline.py)

• Assigned dedicated, high-contrast SVG icons for all submenus and actions:
  • updating_boundaries.svg → Updating of Boundaries submenu
  • check_and_update.svg → Check and Update action
  • others.svg → Others submenu header (high-luminosity amber #F59E0B)
  • sync_mbi.svg → Sync MBI Layer action (electric blue #0288D1 & green #00C853)
  • repair_geom.svg → Geometry Repair Toolkit action (vivid lime green #00E676 & amber wrench #F39C12)
• Synced all SVG assets to icons/ and docs/user-guide/public/icons/.

2. VitePress Config & Navigation (config.mts, index.md)

• Added Check and Update, Scan Geometry Errors, and Repair Polygon Geometries to nav dropdowns and sidebar categories.
• Added feature cards with SVG icons on the home index page.

3. Tool Documentation Formatting & Algorithm IDs (docs/user-guide/tools/)

• Added explicit Algorithm ID entries under ## Access:
  • scan-geometry-errors.md → gmd_pipeline:scangeometryerrors
  • repair-polygon-geometries.md → gmd_pipeline:repairpolygongeometries
  • create-enumeration-areas.md → gmd_pipeline:createea
  • check-and-update.md / geometry-repair-toolkit.md → Component Algorithm IDs
• Removed redundant --- lines before ## headings across all tool guide markdown pages to prevent double horizontal line artifacts.

4. Documentation Skill Protocol (SKILL.md)

• Added Strict No Redundant Horizontal Dividers Standard and Mandatory Algorithm ID Standard rules to qgis-doc-generator.

Verification

• VitePress Build: Ran docs:build — compiled cleanly in 0.94s with 0 errors.
• Dual-Theme Inspection: Checked SVG stroke contrast against #FFFFFF (Light Mode) and #2C2C2C (Dark Mode).