bv v0.19.0

Features

--robot-triage --brief (#183): compact triage output mode for agents that
only need the headline recommendations, not the full analysis payload.
Comments in Pages export (#187): the static Pages export now renders bead
comment threads, so exported boards carry the full discussion context.

Robot-surface agreement / agent-safety (#184): --robot-file-hotspots,
--robot-file-beads, and --robot-impact disagreed for the same path
(3 vs 0 vs "safe to proceed"). File-touching bead counts are now unified
across all three surfaces — no more false "safe to proceed" verdicts
steering agents into files with open beads.
Theme override completion: reliable --theme light|dark selection for
light terminals (bv-128).
Fail-closed robot-next claims: --robot-next claimability no longer
fails open (bd-ifoh3.3).
Export memory (#182): history blobs stream with bounded memory; caches
enabled off-robot.
Gitignore hygiene (#179): prefers .git/info/exclude and adds a
BV_NO_GITIGNORE opt-out.
Viewer: routes host-rewritten clean paths and guards double WASM init on
direct graph entry.