Deep research generated search queries from the LLM's training-cutoff
knowledge, so it emitted stale-year queries like "best Python tutorials
2025" when the actual year is later (issue #1341). The chat/agent path
already grounds the model with "Today is ..." (src/agent_loop.py); the
deep research planning and query-generation prompts had no equivalent.
Add a small current_date_context() helper and prepend it at the plan and
query-generation prompt sites (and the research_handler plan preview path
that reuses RESEARCH_PLAN_PROMPT). System-TZ local, portable strftime.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Deep Research surfaced 'Error: unknown error' whenever every search
provider returned an empty result set without raising (e.g. SearXNG is
reachable but all its engines fail internally). _last_search_error was
only set on exceptions, so the empty-but-no-exception path left it unset
and the caller fell back to 'unknown error'.
Record an actionable reason on that path naming the providers that were
tried, so users can tell it's a search-backend problem rather than a
model problem. The provider-raised path is unchanged.
Re: #344.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>