Unit tests for the safety-critical paths: crypto secret-box (round-trip,
tamper detection, wrong key), the SSRF guard (blocked ranges + DNS-rebinding),
the ai-chat tools service, the page-embedding repo, and the
assistant-parts/serialization helpers. Those server helpers (assistantParts,
rowToUiMessage, serializeSteps) are exported ONLY for the tests — no runtime
change.
Also: keyboard a11y on the chat history header and conversation rows
(role/tabIndex/Enter+Space), and DRY refactors that move shared logic into one
place (isToolPart -> tool-parts util; buildInitialValues in the MCP form).
The behaviour-changing edits that previously rode along in this commit are
split out into the following two commits, per review.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
f1980cf425