Sidebar file preview reveals the most recent Chat

[jeonghun-jj-lee]

Important

Problem — A Sidebar single-click can open Preview inside a hidden Amicode Chat while a native VS Code editor remains active. A fresh Landing draft drops the same request because it has no Preview surface.
Approach — Reveal the most recently active live Chat in place before forwarding the existing Preview request. Give Landing drafts a local Preview pane that reuses the established file-preview workspace without promoting or selecting a session.
Scope — in: recent-Chat activation, draft-local Preview, extension-to-fork regression coverage, and overlay synchronization. Out: session promotion, a new file lifecycle, broadcasting to every Chat, and changing double-click behavior.
Assumptions — A file single-click is a Preview intent; a missing Chat retains the existing native-editor fallback.

Acceptance Criteria

• A Sidebar single-click from a native editor reveals the most recently active Chat and displays the selected file in Preview.
• Multiple open Chats route the file only to the most recently active Chat.
• A Landing draft displays Preview without creating, promoting, or selecting a real session.
• Closing draft Preview hides it; a later Sidebar file selection reopens it.
• With no live Chat, Sidebar single-click retains the native-editor fallback.
• Double-click remains a pinned native editor action.

Testing Decisions

Extend extension-host tests for recent-Chat selection, in-place reveal, message delivery, and the no-Chat fallback. Add browser coverage for Preview in a Landing draft, repeated file selection, close/reopen, and unchanged draft routing. Retain the existing Preview interaction contracts.

Key Decisions

The Sidebar activates an existing Chat tab but never changes its internal session. The extension retains primary-Chat behavior for unrelated callers and adds a distinct recent-Chat lookup for this file-preview flow. Landing Preview is a focused local surface, not the session side-panel subsystem.

Constraints & Invariants

• Existing Preview renderers, file handling, and capacity behavior remain authoritative.
• No Preview request creates a session or changes a draft URL.
• The Chat remains in its existing VS Code editor group when revealed.
• The extension does not use a broadcast delivery path.

Prior Art

• Closed Amicode issue Extension → Preview bridge (sidebar routing) #934 established the Sidebar-to-Preview transport.
• Open opencode PR Retire Project as user-facing concept — align CONTEXT.md with Amicode README / Armonia vision #319 owns the Preview workspace.

Source

Extends #934 and is implemented alongside harmoniqs/opencode#319.

[jeonghun-jj-lee]

Closed: this issue was created in error; implementation proceeded directly at the researcher's request.