docs: Add comprehensive MkDocs documentation with GitHub Pages deployment

[finxo]

Pull Request

📝 Summary

This PR establishes a complete MkDocs-based documentation system for Titan CLI with automated GitHub Pages deployment. The documentation covers core concepts (workflows, plugins, AI integration), detailed guides for all major workflows, and comprehensive references for configuration, steps, and hooks.

🔧 Changes Made

• Added MkDocs configuration with Material theme and extensive navigation structure
• Created comprehensive documentation covering concepts, guides, and reference materials
• Implemented GitHub Actions workflow for automated docs deployment to GitHub Pages
• Added Makefile targets for local docs serving, building, and deployment
• Configured Poetry with docs dependency group (mkdocs, mkdocs-material, pymdown-extensions)
• Removed legacy Jekyll configuration (_config.yml)
• Documented all built-in workflows (commit-ai, pr-ai, jira-analyze, etc.) with examples
• Created reference documentation for configuration files, step types, and hook system
• Added troubleshooting guides and FAQ section
• Included getting started guide, installation instructions, and development setup

🧪 Testing

• Unit tests added/updated (poetry run pytest)
• All tests passing (make test)
• Manual testing with titan-dev

Documentation was manually tested by:

• Running make docs-serve to verify local rendering
• Testing make docs-build to ensure clean build output
• Validating all internal links and navigation structure
• Reviewing rendered output in browser for formatting and readability

📊 Logs

• No new log events

✅ Checklist

• Self-review done
• Follows the project's logging rules (no secrets, no content in logs)
• New and existing tests pass
• Documentation updated if needed

[wiz-c04d923138]

Wiz Scan Summary

Scanner	Findings
Vulnerabilities	-
Sensitive Data	-
Secrets	-
IaC Misconfigurations	1
SAST Findings	-
Software Management Findings	-
Total	1

View scan details in Wiz

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[wiz-c04d923138]

 IaC Finding

Workflow should not use version pinning for third-party actions
on resource jobs.deploy.steps[2].uses

More Details

This rule checks that GitHub workflow does not use version pinning on third-party actions. This rule fails when the workflow contains steps that use third-party actions referenced by version tags (like @v1, @v2.3, @v4) instead of specific commits. Using version-tagged actions creates a supply chain security risk, as the version tag could be modified by the action's maintainer to point to malicious code after the calling workflow is created. Even when using specific version tags, the tag could be moved to point to malicious code. To prevent this risk, always pin third-party actions to specific commit SHAs to ensure the exact code being executed is locked and immutable.

Expected

Workflow job 'deploy' step[2] should pin third-party action to a commit SHA rather than a version tag

Found

Workflow job 'deploy' step[2] uses version-tagged third-party action: 'snok/install-poetry@v1'

Security Frameworks: wf-id-1, wf-id-175

Rule ID: 7d431072-4eef-466b-b469-4b7681d8f9a1

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