feat(agent): track Agent GUI engagement

[chovy-ai]

Summary

• add true Agent chat panel exposure tracking after 1 second at 50% visibility
• track first composer focus with pointer, keyboard, or programmatic modality
• track first privacy-safe content entry per panel visit for text, images, and large text
• wire the analytics contract into workspace and standalone Agent GUI surfaces
• document ownership, exposure semantics, deduplication, and privacy constraints

Privacy

No prompt text, file names, file paths, mention URIs, or attachment payloads are collected. Events contain only IDs, enums, booleans, provider/surface metadata, and a per-visit correlation ID.

Validation

• pnpm check:changed (9/9 lanes)
• pnpm check:agent-activity-runtime-boundaries
• pnpm check:renderer-boundaries
• pnpm lint:ts
• pnpm --filter @tutti-os/agent-gui typecheck
• pnpm --filter @tutti-os/desktop typecheck
• focused Agent GUI analytics/editor tests (65 passed)
• full Agent GUI suite (2245 passed)
• full Desktop suite (1316 passed, 2 skipped)
• pnpm --filter @tutti-os/desktop build
• pre-push pnpm check:full (16/16 tasks)

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Summary by cubic

Adds privacy-safe Agent GUI engagement analytics that track true chat-panel exposure, composer focus modality, and the first user-entered content per visible visit. Events are wired through the desktop analytics pipeline for both workspace and standalone Agent surfaces.

• New Features
  • Emits agent.chat_panel_exposed, agent.chat_input_focused, and agent.chat_input_content_entered.
  • Exposure requires active node, document visible/focused, and ≥50% in viewport for 1s; previews excluded; interactions buffered and emitted post-exposure with a shared panelVisitId.
  • Focus preserves modality: pointer, keyboard, or programmatic.
  • Content reports only the first user-entered text, image, or large_text per visit; ignores prefill/controlled hydration.
  • Introduces optional engagementAnalytics callbacks in @tutti-os/agent-gui; desktop host constructs reporters and passes them to workspace and standalone_agent surfaces.
  • Privacy: no prompt text, file names/paths, mention URIs, or attachment payloads are sent; only IDs/enums/booleans and surface metadata.

^{Written for commit 40ba47c. Summary will update on new commits.}