docs(devtools): document preview mode, read-only display mode and context warnings

[harijoe]

The DevTools page is behind the build ahead of v1.4.0: preview mode is undocumented, and the page still describes the display mode as a control you switch.

Summary

• New Preview in a Host Conversation section: the preview button, the ChatGPT/Claude client switch, the phone frame, how the three display modes behave, and the host context (ui/initialize style variables, container dimensions, available display modes) injected while preview is active.
• View preview bullet no longer lists display mode as a live control. It is a badge now, driven only by the view (feat(devtools): read-only display mode and panel-bounded fullscreen (SKY-536) #1048), and the WebMCP bullet drops it too, matching devtools_set_view_options.
• New Context warnings bullet for the 5,000 / 20,000 estimated-token badges from DevTools: warn on large tool output and view state #1040.
• One runtime limitation was inverted: the preview mocks the MCP Apps runtime, not the Apps SDK one, since the runtimes were unified in v1.2.0.

Verification

mintlify broken-links clean (the two new anchors and /api-reference/use-mcp-app-context resolve).

[mintlify]

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Project	Status	Preview	Updated (UTC)
skybridge-staging	🟢 Ready	View Preview	Aug 11, 2026, 1:36 PM

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[greptile-apps]

Greptile Summary

The PR updates the DevTools documentation to match the current preview and inspector behavior.

• Documents host-conversation preview shells, client/device switching, display-mode behavior, and injected host context.
• Adds context-warning thresholds and clarifies that display mode is view-controlled.
• Correctly describes both the MCP Apps mock and Apps SDK shim, with a new preview screenshot.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

_{Reviews (3): Last reviewed commit: "docs(devtools): add preview mode screens..." | Re-trigger Greptile}