- **Finding 1 (bug):** a delete starting exactly at a fold's `end`
removed the `\n` that `end` names — the last hidden line's terminator —
but the strictly-after arm (`os >= e`) kept the fold, leaving a mid-line
end. `translate`'s after-arm is now `os > e || (os == e && old_len == 0)`
so a pure insert at `e` still stays outside while a delete at `e` falls
to the drop arm, symmetric with the head side. New unit test
`delete_starting_at_tail_boundary_drops_fold` (bite-verified).
- **Finding 2:** `pmacs.buffer.kill` didn't clean the fold registry.
Added `FoldRegistry::forget_buffer(id)` (id-keyed; the view died with the
buffer) and wired it into `after_buffer_removed`, mirroring the
keymap/config cleanup; the registry is now stashed as Lua app-data.
`forget(&mut Buffer)` is clarified as the revert/reload reset.
- **Finding 3:** `fold.close-all` now moves the invoking point to the head
when it closes a fold around it (Q#FD3); the data-API `fold` exemption
(programmatic, no invoking point) is named in the module doc.
- Nits: dropped the dead `!(both empty)` conjunct in `fold_state_msg`;
replaced the trivial fresh-registry assert; added coverage for the
stale-tree refuse via a fold command, the read-only-buffer rejection
(Q#FD11), and unfold normalizing an arbitrary range.
Gates green: fmt, clippy --workspace --all-targets, --lib (1786),
--features crdt (1962), folding_acceptance (24), m4 (skip basedpyright),
required-GPU, git diff --check.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Q5BkezMppbpCgGAYk2ftxV
Levi Neuwirth
9691dd4e9f