Parse complete source and donor vision blocks, then insert literal pole
payloads with owned trailing separators before prompt content. Preserve one
shared study layout and exact original token recovery and projection.
Keep verified newline carriers whole and track native output stripping
separately, retaining native role/header tokens for merged carriers. Reject
unknown carriers and malformed role or media prefixes before study encoding.
Preserve native anchoring, negative, metadata, deepstack, gain and timing.
All 219 tests and required compile checks pass. Causal scalar fixtures include
the previous append layout as a negative control; saved native mask and strip
bookkeeping agree with declared nonneural boundaries. Visual effect remains
unverified.