The 'KeydbSource owns save+update' (Added) and 'Processing-Key
decryption restored' (Fixed) entries were stale carryover from the
never-released 1.1.0-beta.1; that code shipped in v1.1.0 (zero diff in
v1.1.0..HEAD). The 1.2.0 entry now lists only the real 1.2.0 changes
(hex unification, DiscInputs version stride, MKB cap).
Move the keydb save/validation/atomic-write path out of libfreemkv onto
KeydbSource. New KeydbSource::save(bytes) validates + decompresses (zip /
gz / plain, decompressed-size capped) and crash-safely writes to the
source's OWN path (sibling-temp + fsync + rename + parent-dir fsync) —
not a hardcoded default, so the caller chooses the destination.
KeydbSource::update(fetch, url) calls an INJECTED fetch closure then
save, keeping this crate transport-agnostic on the update path (the app
supplies its own TLS / SSRF-guarded transport). UpdateResult moves here
and is re-exported. Add flate2 + zip (already in the resolved graph via
libfreemkv) for decompression; no new HTTP stack.
unit_keys_from now resolves the Media Key in order: stored per-disc MK
-> keydb Processing Key pool (mk_from_pk vs this disc's own MKB) ->
device-key pool (mk_from_dk), then MK+VID -> VUK -> UK. MK/VUK entries
still honored directly; cross-disc MK-pool brute stays retired. Fixes the
factually-wrong justifying comment + adds PK-pool KATs.
Matthew Jackson