docs: RE notes for int-encoder, registry, name-filter, Phase-1 recipe, gdb lessons, Phase-2 plan

Adds §9 int32 encoder (0x3c8e70, zigzag+varint, ABI), §10 encoder registry
(0x45f360, InitFakeField 0x34b980, full map), §11 corrected fieldInfo layout
(name@+0x08 is the reliable id; +0x40 reads 0, NOT m_nFieldOffset), §12 working
Phase-1 value spoof recipe, §13 tooling lessons (gdb kill-9/FIN-WAIT-2 trap,
catch-load suppression, Ghidra-12 Jython, .assets plural), §14 Phase-2 per-client
plan. Table updated.

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