Install detours at startup + struct-dump diag for quantized fields

Move encoder/substitution detour install from lazy-on-first-registration to
PostInit (server start). A lazy install of 17 encoder detours mid-game stalled
a full frame (~120ms) the first time a spoof was set; installing at load keeps
gameplay smooth. Both Ensure* installers are idempotent so the lazy paths
become no-ops.

Enrich UENC-DIAG to dump the real value-struct (count@+0x28, float[0..2]) so we
can confirm the quantized/qangle struct copy is valid vs garbage.

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