The "Copy chat" button was hidden during a brand-new chat's very first
turn: both the `canExport` gate and the `handleCopy` early-return required
an `activeChatId` AND persisted `messageRows`, neither of which exists yet
while the first turn is streaming or after it was interrupted before any
row was persisted.
Decouple the export gate from persisted state. ChatThread now reports a
reactive `onLiveContentChange(messages.length > 0)` signal (the live
snapshot lives in a non-reactive ref, so a separate reactive flag is
needed to re-render the button); the parent keeps it in `hasLiveContent`
and exports whenever there is anything on screen OR persisted. `handleCopy`
passes a `"unsaved"` placeholder chat id when none exists yet, and the
live-first builder serializes the on-screen thread WYSIWYG.
Builds on #160 (WYSIWYG export); covers the first-turn edge case that was
explicitly out of scope there.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
"Copy chat" built the Markdown from persisted rows plus a live tail that was
only included while isStreaming. When a turn was interrupted (dropped stream /
"Lost connection" banner) isStreaming flipped false, the live tail was dropped,
and the partial assistant reply visible on screen — whose row often never
persisted — vanished from the export, leaving only the user messages.
- buildChatMarkdown is now live-first: the on-screen `live` messages ARE the
document. Each is matched to a persisted row by id to enrich it with token
usage / error / timestamp; authoritative usage/error already on the live
message win over the row. When `live` is empty it falls back to the persisted
rows (old format preserved). Only the tail assistant is flagged "still
generating", and only when it is genuinely the streaming tail — so the
status==="submitted" window (tail is the user message) never mislabels the
previous, completed answer.
- The on-screen banner (classified error / dropped connection / manual stop) is
flattened to a string in ChatThread, mirrored into liveStateRef alongside the
messages/isStreaming snapshot, and appended at the end of the export.
- handleCopy maps the live messages and passes live/rows/isStreaming/banner.
Tests: chat-markdown rewritten for the live/enrichment/fallback/banner paths and
the submitted-window regression (26); full ai-chat suite green (186). tsc clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
