sqlite moves into the sx library: import vendors/sqlite/sqlite.sx

The amalgamation and the bindings now ship with sx itself
(sx library/vendors/sqlite/ — bindings + c/ amalgamation); every
import flips from ../src/db/sqlite.sx to vendors/sqlite/sqlite.sx,
resolved through the compiler's stdlib search paths. vendor/ and
src/db/ leave this repo entirely. make test 22/22 — the object cache
keys on content, not path, so the relocated source still hits the
existing cache entries.

tests/server_write.sx

@@ -30,7 +30,7 @@
 process :: #import "modules/std/process.sx";
 fs   :: #import "modules/std/fs.sx";
 hash :: #import "modules/std/hash.sx";
-sq   :: #import "../src/db/sqlite.sx";
+sq   :: #import "vendors/sqlite/sqlite.sx";
 
 STORE   :: ".sx-tmp/server_write";
 PORT    :: "18793";