docs(ai-agents): update Deep Research behavior

[sdolidze]

Closes: https://linear.app/lightdash/issue/PROD-9426/update-deep-research-docs-for-current-product-behavior

Summary

Updates the Deep Research guide to match the product behavior shipped after the previous documentation refresh.

What changed

• Documents live query-backed report charts, read-only report interactions, Explore handoff, Beta labeling, and the report contents rail.
• Adds organization-level raw SQL controls and the existing SQL Runner permission requirement.
• Explains unavailable MCP-server handling, warehouse-limit recovery, no-relevant-data outcomes, and failed-run restart behavior.
• Removes obsolete confidence-label and chart-snapshot descriptions.

attached sources ──┬─ healthy tools ──> investigation ──> live report charts
                   └─ unavailable ───> skipped
warehouse limit ──────────────────────> narrow query ×2 ──> partial evidence

Test plan

• node scripts/check-links.js
• node scripts/check-image-locations.js
• git diff --check

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Project	Status	Preview	Updated (UTC)
lightdash	🟡 Building	–	Aug 11, 2026, 5:02 PM

[linear-code]

PROD-9426

[github-actions]

🤖 Documentation Bot

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