- DiffBlock: an empty side contributes zero lines and a trailing newline is a
terminator, so a create ending in a newline draws one added line (not a
phantom empty one) and a full deletion draws no phantom + line.
- diffCardModel: narrow the wire diffs payload (card is the only validated
field) so a malformed diff card falls back to the generic path instead of
throwing inside DiffBlock.
- FileMutationRow: surface the result text when an errored mutation has no diff
card, so a failed edit/write is more than a red dot.
- copyText ends its closed union on assertNever.
- Docs: drop the "bridge relativizes" claim, record the file-count divergence
from the TUI footer, correct the built-boot overclaim, note why the row title
outranks the view title, and make fixture turn 67 args self-consistent.
- Tests: terminator/empty-side/interior-blank rows, wire-narrowing null arms,
the error-text arm and its name/code fallback, stopped state, no-path summary,
and the registration/disposal shape.
The write/edit tools already declare card:'diff' with applied hunks on
callView/resultView, but the Web client discarded it: a mutation landed on
GenericToolCard and the details panel flattened the result to a <pre>. Add
DiffBlock (ui-primitives), diff-card-model (the single callView/resultView
derivation), and FileMutationRow (keyed under write and edit), and make the
generic fallback row and the details panel diff-aware. The +/- block form,
per-file path header, same-file gap, and footer mirror the TUI diff card;
the chat row caps at CHAT_DIFF_MAX_LINES against the panel's full height.