Fix D203/D253: Facility SIGSEGV on Linux — callback prototype ABI mismatch

stanCheckLinkedSpecialTile was decompiled with an all-s32 middle-arg
prototype while its callers pass it through the standTileLocusCallback_B_t
typedef (f32 f32 f32). On x86-64 SysV the int/float class split puts the
6th arg (outFlags/record) in %rdx per the typedef but %r9 per the
definition, so the FORCECROUCH/LADDER store hit a stale scratch register.
MIPS o32 passes both through GPRs a0-a5 identically, which is why the
mismatch was invisible on N64 and in the decompilation.

ABI-class edit (AGENTS.md #2 narrow exception): body never uses the three
middle params; N64 codegen unaffected. Verified under gdb on WSL:
pre-fix SIGSEGV at stan.c:2441 with r9=0x3 and a valid record in the
caller frame; post-fix the same walk route completes clean.

.github/release-notes.md

@@ -19,7 +19,10 @@
   green/pulsing; reflective surfaces (glass, chrome weapon skins) work.
 - **Crash fixes**: the two v0.1.0-era crashing levels (Bunker ii, Statue) and
   the AI-pacing bug that broke Cradle are fixed and playtest-verified — all 21
-  solo missions load and run crash-free.
+  solo missions load and run crash-free. Also fixed: the Steam Deck / Linux
+  Facility crash triggered by walking into the crouch-forcing spot at the
+  level's opening (D253) — this also revives the auto-crouch and ladder
+  signals, which were dead on PC before.
 - **QoL**: F10 in-game options overlay (fullscreen, resolution, frame cap,
   MSAA, texture filtering, FOV/draw distance, sensitivity), mute-on-focus-loss,
   F12 screenshot.