Both desktop-app's app.rs and the new Android transcript client (RUST.md's
I5) need the same page-fold and live-stream resume-cursor logic; per
CODE_RULES's "write the logic once" it now lives in client-core alongside
fold_event/group_tool_runs instead of being duplicated. desktop-app calls
the shared functions; its own copies and their tests moved with them.
Also fixes a clippy::collapsible_if in config.rs's percent_decode, found
while re-running clippy after this change (let-chains are stable now).
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
irisandClaude Fable 5.1
78aff64844