Previously, scan_keys discarded any key found in WeChat's process
memory that didn't match a known DB file's salt. If DB files were
inaccessible during `wx init` (permission issues, path resolution
failures), zero keys were saved and decryption silently failed.
Apply the same logic as khipuchat's wechat-key-extract.c: save all
(key, salt) pairs found in memory unconditionally. Keys that match
a DB file by salt are stored under the relative DB path as before.
Keys with no match are stored under `_by_salt/<salt_hex>` so they
are never lost.
The daemon's DbCache::get_with_mode gains a fallback: if a DB's
rel_key is not in all_keys, it reads the DB file's first 16 bytes
to get the salt and retries the lookup as `_by_salt/<salt>`.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Yanick Landry
jackwener