HenryHe520/dsh-time-pin

Gives one conversation a pinned as-of point and a dated evidence window on both sides — \[as_of − before, as_of + after], past, future or BC. In restricted mode the agent is told the active window once per change, web_search results are filtered to dated sources inside the window and undated sources are rejected, and the first reply must echo the window (a missing echo gets one nudge). It also narrates long silent background jobs with deterministic \[TIME FACT] facts and exposes a read-only time_pin_status tool; default mode injects nothing and filters nothing.