sync lua ffi bindings with tidesdb db.h abi and bump to 0.7.1

[guycipher]

add missing public bindings init finalize raise open file limit cancel background work and the s3 object store connector factories both the positional and full config forms with a graceful error when the library is built without s3 support

fix abi struct drift that caused out of bounds writes the config struct was missing finish compactions on close so the by value default config return overflowed and open read past the buffer the db stats struct was missing eight trailing write amplification counters so get db stats wrote sixty four bytes past the caller buffer and the cf stats struct was missing seven write amplification fields

add the busy error code at minus fourteen and expose the new write amplification counters in both cf stats and db stats

correct the max concurrent flushes test the engine default is now zero meaning use the internal default rather than greater than zero

add eight tests covering all of the above forty nine passing and extend the lua reference docs with the new functions config flag stat fields and s3 connector usage