Problem: `M.list` returned entries as `{0, name, type, meta}`.
`cache.store_entry` only assigns a fresh ID when `entry[FIELD_ID] == nil`;
passing 0 caused every entry to be stored as ID 0, all overwriting
each other. `get_entry_by_id(0)` then always returned the last-stored
entry, breaking navigation (always opened the same file), rename
(wrong entry matched), and create (wrong diff).
Solution: change the placeholder from 0 to nil, matching how
`cache.create_entry` itself builds entries.
Barrett Ruth
ba27fe176b
