fix: SerializerSingleton Linux sig was non-unique (didn't resolve)

The force-resend serializer-singleton global sig (engine, Linux) was constructed from
the decompile pattern and its tail matched 2 sites in libengine2.so → FindPattern
rejected it → 'SerializerSingleton not resolved' at load (harmless while force-resend is
gated, but wrong). Re-derived from the actual load site (0x7d17cb): MOV RDI,[rip]; MOV
R13,[r12+0x8f8]; MOV ECX,[rax+0x18] — tail is unique (1 hit). Lint-verified all Windows
sigs unique too; only this one was broken.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>