- fmt_builtin_tool: Edit gets its own arm computing `-N +M` line counts
in _summary (was shared with Read/Write as bare file-path).
- is_rich_tool: drop Write (content is huge/one-sided; flat _summary row
is correct); Edit stays rich since it has an old/new diff.
- rich_tool_body: now returns Option<(String, &'static str)> where the
second field is the body type ('diff' or 'plain'). Edit arm builds the
'-'/'+ ' prefixed diff body; mcp__bash__run gets type 'plain'.
- enrich_tool_use_entry: stamps both _body and _body_type.
Frontend (app.js):
- Remove the Write/Edit branch from renderRichToolUse (~25 lines).
- Generic _body path now dispatches on _body_type: 'diff' ->
api.detailsDiff (colour-coded spans), default -> api.details.
No tool-specific JS remains for file diff rendering.
0e4b69dd20