feat(web): preview generated images in right panel

[kyzer1023]

Problem

Completed Codex image-generation activities render their saved filenames in the transcript, but selecting one follows the normal workspace-file path. In the desktop app that hands the image to the configured editor instead of previewing it inside T3 Code.

Solution

• Preserve the generated image path while projecting Codex image-generation activities.
• Resolve that path server-side and issue a short-lived capability for the exact image file; sibling and traversal requests remain inaccessible.
• Open generated images as reusable, thread-scoped right-panel tabs with loading, failure, refresh, and close behavior.
• Document the user-visible web and desktop behavior.

Other providers are unchanged because this is based on Codex's existing imageGeneration activity payload.

Impact

Users can inspect a generated image without leaving their conversation or opening an external editor. Reopening the same image refreshes and activates its existing tab instead of creating duplicates.

Validation

• 219 focused server and web assertions passed.
• t3, @t3tools/web, and @t3tools/contracts typechecks passed.
• Targeted formatting passed.
• Review hardening preserves filesystem-significant path whitespace and rejects request-time canonical path changes such as a symlink swap.
• Reopening a generated image uses a new cache-busting URL so updated bytes are fetched immediately.
• Generated-image lookup reads only the selected activity's saved path instead of hydrating the full thread.
• Manually verified by the contributor in T3 Code (Dev) on Windows: selecting a generated image opened it in the right panel and did not launch the external editor.

The full AssetAccess.test.ts file currently has two pre-existing Windows-only favicon assertions that expect / instead of the native \ separator. The generated-image cases pass independently, and this change does not modify those favicon paths.

Screenshots

Before

After

Coordination

The contributor requested review before #2829 lands. The implementation may need adaptation when orchestration V2 merges.

Authored with GPT-5.6 in T3 Code using the Codex harness.

Note

Add generated image preview panel to the chat right panel

• Completed image generation activities are surfaced as standalone work log entries in the timeline with a clickable link that opens the image in the right panel.
• A new generated-image right panel surface kind tracks activityId, name, and a loadRequestId counter; each call to openGeneratedImage increments loadRequestId to cache-bust the asset URL.
• GeneratedImagePanel fetches the image via useAssetUrlState, appends a t3LoadRequest query param, and shows loading/error states.
• The server resolves the image file path via a new ProjectionSnapshotQuery.getGeneratedImagePath SQL query and issues a signed asset URL through assetsCreateUrl WS method using a new generated-image AssetResource variant.
• Activity payloads with itemType: 'image_view' are now projected to expose only fileName (no savedPath) to the client.
• Persisted right panel state is migrated to version 12; invalid generated-image surfaces are dropped on migration.

^{Macroscope summarized 89b8332.}

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Note

Medium Risk
Touches signed asset issuance and filesystem path validation for provider files; mitigations include exact-file tokens, symlink rejection, and activity-scoped lookups.

Overview
Adds in-app preview for completed Codex image-generation activities instead of treating them like workspace file links.

Server: New generated-image asset resource resolves the provider savedPath via a narrow projection lookup (getGeneratedImagePath), issues signed URLs with generated-image claims, and serves only the exact basename with canonical-path and symlink checks. Activity projection strips full paths from payloads (filename only).

Web: Work log rows expose a link that opens a reusable right-panel tab (GeneratedImagePanel) backed by signed asset URLs and a loadRequestId cache-bust on reopen. Timeline folding keeps generated-image links visible after tool activity collapses.

Docs: User guide for generated image preview.

^{Reviewed by Cursor Bugbot for commit 89b8332. Bugbot is set up for automated code reviews on this repo. Configure here.}

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[macroscopeapp]

One finding: the generated-image branch of assetsCreateUrl wraps a projection-read failure in an error whose semantics (and caller-visible message) describe filesystem inspection of the image. Everything else in the changed Effect code follows the conventions (namespace subpath imports, structured Schema.TaggedErrorClass errors with cause and derived messages, errors constructed at the failure boundary, no hidden runtimes or service-instance injection).

^{Posted via Macroscope — Effect Service Conventions}

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 2 potential issues.

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^{Reviewed by Cursor Bugbot for commit 62a40ae. Configure here.}

[macroscopeapp]

Approvability

Verdict: Needs human review

New feature introducing user-facing image preview capability with new UI components, state management, asset types, and server-client integration. New features with this scope warrant human review.

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