feat: show message info on click - #2802

Fixed in aafa249. The collector in _chatStreamWithCostAllowance now preserves the terminal reason from the provider done chunk (and its raw payload when present) and passes it into the result, so aggregateMessageCompletion can read result.finishReason instead of always receiving an empty reason on the primary streaming Ask path. The streaming providers that actually observe a terminal reason (OpenAI Chat Completions choice.finish_reason, Anthropic message_delta.delta.stop_reason, llama.cpp / Azure choice.finish_reason, Bedrock stopReason) now attach it to their done chunk. The Responses API has no per-generation stop reason, and the aggregation test already treats lifecycle status as not-a-reason, so no value is fabricated there. Verified: node test/run.js 1755 passed.

Confirmed fixed in 5b116dc: the synthesized run_complete in applyActiveRunState now includes data.endedAt: runUi.endedAt, so terminal restore uses the snapshot completion time instead of falling back to request-start/panel-open. The new behavioral test asserts the replaced sent time is retained across restore.

Mirrored in 5b116dc on the Firefox sidepanel; covered by the same behavioral restore assertion in the new test.

Fixed in aafa249 with a semantic toggle button, per your suggestion:

• Each message with a timestamp now gets a real <button type="button" class="message-info-toggle"> as a sibling of the info row (outside the bubble, so no nesting inside the message links/buttons), carrying aria-expanded and aria-controls pointing at a stable row id (message-info-<n>).
• The message div no longer receives tabIndex = 0, aria-expanded, or a keydown handler; keyboard users activate the toggle button directly.
• Bubble-click delegation is retained as a mouse convenience, and clicks on the button are excluded from it via the existing messageInfoClickIsInteractive guard.
• refreshOpenMessageInfoRows refreshes the button label instead of the div title; restored messages re-create/reuse the button through messageInfoToggleButton.

One deliberate design note vs. a role="button" on the bubble: a real <button> gives native Enter/Space handling, focus management, and correct AT announcements, which a div with aria-expanded alone cannot — this matches your recommendation.

Mirrored in aafa249 — the Firefox sidepanel implements the same semantic toggle button (aria-controls/aria-expanded on a real button, stable row id, no tabIndex/aria-expanded/keydown on the bubble div, bubble-click delegation kept). Both builds covered by the new behavioral test.

cc/ @alectimison-maker 🙏

Addressed in aafa249 with a behavioral DOM test (message info toggles behaviorally through a semantic button, terminal replay, and restore in both builds). It extracts the real message-info functions from each sidepanel via vm and drives them with a small fake DOM, exercising: toggle via bubble click and via the semantic button, aria-expanded/aria-controls sync, applyMessageCompletion → dataset round-trip, terminal replay (run_complete endedAt replacing the sent time via setMessageCreatedAt(..., { replace: true })), and a restore round-trip that rebuilds a message from persisted datasets + the open class and asserts the completion timestamp and metrics are retained. The repo test runner is deliberately dependency-free ("pure Node, no framework"), so this follows the same vm-extraction pattern as the existing /print behavioral tests instead of adding jsdom.