Fix Android pthread metadata before mobile shared linking

Patch crypton and direct-sqlcipher before planning: Bionic supplies pthread in libc and the NDK has no separate libpthread. Preserve compiler threading flags and the shared-link adapter.

Check Android-only source selection and allow the existing Android CI group to be dispatched independently for final-link validation.

scripts/nix/direct-sqlcipher-android-pthread.patch

@@ -0,0 +1,12 @@
+--- a/direct-sqlcipher.cabal
++++ b/direct-sqlcipher.cabal
+@@ -91,9 +91,6 @@
+
+     extra-libraries: dl
+
+-    if !os(windows) && !os(android)
+-      extra-libraries: pthread
+-
+     if flag(fulltextsearch)
+       cc-options: -DSQLITE_ENABLE_FTS3 -DSQLITE_ENABLE_FTS3_PARENTHESIS
+                   -DSQLITE_ENABLE_FTS4 -DSQLITE_ENABLE_FTS5