Docs: Add Context Center guide for v2.0.x-SNAPSHOT

[kiran1287]

Summary

• Adds a new "Context Center" section to the v2.0.x-SNAPSHOT docs, covering Articles, Memories, Documents, and the Dashboard landing page
• Adapted from docs-collate PR #503's ai-2-0/collate-ai/context-center/ pages for the OSS product (removes Collate-only branding, reuses OpenMetadata's existing search_company_context/get_company_context/create_context_memory MCP tool names)
• Verified against OpenMetadata source: contextMemory.json schema, RBAC resource categories in resource-scope.mdx, and the actual ContextCenter* UI routes/components
• Registers a new top-level "Context Center" nav tab (parallel to Data Discovery, Data Contracts, Data Collaboration), plus cards on the How-to Guides home page and the v2.0.x-SNAPSHOT homepage "What's New" section (which also now calls out the new Prefect and Omni connectors)

Test plan

• docs.json validated as well-formed JSON
• All image references resolve to files in this PR
• All internal links and same-page anchors resolve
• Content reviewed against the doc style checklist (no em-dashes, no Latin abbreviations, active voice, no leaked Collate branding)
• Visual check in Mintlify preview once deployed

[mintlify]

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Project	Status	Preview	Updated (UTC)
openmetadata	🟢 Ready	View Preview	Aug 21, 2026, 3:35 PM

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