Research agents must now tag every factual claim with its source:
[VERIFIED], [CITED], or [ASSUMED]. An Assumptions Log section in
RESEARCH.md collects all [ASSUMED] claims so downstream agents and
users can identify decisions that need confirmation before execution.
Prevents unvalidated assumptions (e.g. "audit logs should be permanent")
from propagating unchallenged through research → planning → execution.
Closes#1431
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>