- KEY_TO_UUID now stores weight (30 bytes: uuid+type+ts+deleted+weight)
- UUID_OFFSETS changed to composite key for O(log n) max-offset lookup
- Add NODES_BY_TYPE index for efficient type+date range queries
- Add for_each_key_weight() to StoreView for index-only iteration
- match_seeds uses index-only path when content not needed
- Fix transaction consistency in ops (single txn for related updates)
- rebuild() now records all uuid→offset mappings for version history
- Backwards compatible: old index formats decoded with default weight
Co-Authored-By: Proof of Concept <poc@bcachefs.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
