Address review findings in the Deep Research backend:
- Escape an unbalanced ")" in citation destinations so a source URL cannot
close the markdown link early and inject a second link, keeping balanced
parentheses literal.
- Match raw-URL citations on whole tokens so a URL sharing another URL's
prefix is no longer partially rewritten.
- Redact non-global IPv6 addresses in public search queries, matching the
existing IPv4 handling.
- Detect credential key names after normalizing case and separators so nested
openaiApiKey, accessToken, and clientSecret values cannot be persisted.
- Reject client edits to server-managed research prompts and reports at the
storage layer; only the internal writers pass allow_research_update.
- Scope research searches to the first allowed domains instead of dropping
site scoping for large allow lists.
- Persist the same fetch evidence bound used during live synthesis so a
resumed run is not shortened.
- Scope run completion so it only replaces this run's message parts.
Add regression tests for the above.