Implement version-specific MkDocs configuration for v0 and v1 documentation

[Copilot]

The v0 and v1 documentation dropdown links were displaying identical content regardless of selection. This PR implements separate MkDocs configurations to properly reflect version differences: v0 (AnnoRank) excludes XAI pages while v1 (XAnnoRank) includes them.

Changes

• New mkdocs-v0.yml configuration: Stripped-down v0 config with navigation excluding XAI pages (XAI Configuration, XAI Ranking App, XAI UI Functionalities)
• Updated mkdocs.yml: Explicit navigation structure for v1 that includes all XAI-related pages
• Updated deploy workflow: Modified .github/workflows/deploy-docs.yml to use --config-file mkdocs-v0.yml during v0 build and deploy steps
• Added gh-pages sync: Integrated gh-pages branch synchronization to prevent concurrent push conflicts during dual-version deployments

Example

The workflow now correctly builds each version:

# For v0 (AnnoRank)
- name: Build site
  run: mkdocs build --config-file mkdocs-v0.yml

# For v1 (XAnnoRank) 
- name: Build site
  run: mkdocs build  # Uses default mkdocs.yml with XAI content

When users select v0 from the dropdown, they see AnnoRank docs without XAI. Selecting v1 shows XAnnoRank docs with full XAI support.