fix(phase-30 T6): byte-neutral decl conforms unblock the SC07 EXTEND lane

The dedup_extend SC07 lane banked 0/36. Captured every failure's own compiler
error rather than guessing: 5 PLUMBING (declaration conflicts) + 4 DIFF per
binary, and the PLUMBING set reduces to 4 distinct symbols repeated across all
four binaries.

Fixed at the lowest available blast radius, each byte-neutral BY CONSTRUCTION
and proven by R22:

- func_80146C3C (8 of 36): T2, but 1 token. DEFINE_func_8016A08C /
  DEFINE_func_8016A1CC declared it `(void)` while the SC07 TUs declare
  `(u8 *a0)`. Both macros already CAST at the call site, so the prototype is
  codegen-irrelevant -> relax to `()` (no-prototype). Measured first: all 4,020
  fleet decls are (void)/()/(u8*)/(u8 *a0) — no default-promotion param
  anywhere, so `()` is compatible with every one of them (the gcc-2.7.2 `()`
  dead-end needs a promoting param; there is none).
- func_8014F4C0 (4 of 36, self-axis), D_80126CC4 (3), func_8012E5CC (1): T1
  binary-local. Conformed the SC07 decls to the fleet-canonical form. Every one
  has ZERO uncast uses in its TU (verified per file), so the decls were pure
  splat boilerplate with no codegen effect.

Deliberately NOT touched: engine_core.h beyond those 2 lines. The §29 law is
about BULK header edits (the 2,046-file sed that still didn't build); 2 targeted
macro lines with a measured compatibility argument is not that.

R22 clean-fleet: make clean && extract-all && check-all -> 140 passed, 0 failed
of 140. Enabling change only; no function banked in this commit.

Method note (mine, recorded): I read `corpus.stubs` while `make extract-all` was
mid-flight and got garbage — R32's coverage assertion refused to answer instead
of returning a wrong stub set. A measurement taken during a rebuild is not a
measurement (S27's law, re-earned). Also: `nohup CMD &` inside a backgrounded
Bash call makes the harness signal completion of the WRAPPER, not the campaign —
the R22 "finished" at 63/140. Waited on `pgrep -x make` instead.

src/ov_SC07_006/ov_SC07_006_jr_80140608.c

@@ -365,7 +365,7 @@ extern s32 func_8012E504(s32 a0, s32 a1);
 extern s32 func_8012E544(s32 a0);
 extern s32 func_8012E57C(s32 a0, s32 a1);
 extern s32 RotTransPers(s32 a0, s32 a1, s32 *a2, s32 *a3);
-extern void func_8012E5CC(s32 param_1, u16 param_2, u16 param_3);
+extern s32 func_8012E5CC(s32 a0, s32 a1, s32 a2);
 extern void func_8012E688(s32 param_1, u16 param_2, u16 param_3);
 extern s32 func_8012E778(int param_1, int param_2);
 extern void func_8012E88C(u8 *a0);
@@ -536,7 +536,7 @@ extern void func_80136C54(void);
 extern void func_80136D00(void);
 extern void SetLineG2(void *);
 extern void func_80136D08(s32 arg0, s32 arg1);
-extern u16 D_80126CC4;
+extern s16 D_80126CC4;
 extern M2C_UNK func_800153CC(M2C_UNK, u16, M2C_UNK, M2C_UNK, s32, s32);
 extern void func_80136DFC(void);
 extern void func_80136EC4(void);
@@ -3366,7 +3366,7 @@ DEFINE_func_801472F0()  /* dedup: shared engine-core @0x801472f0 (src/shared) */
 extern s16 currentLocationId;
 extern s32 D_80126B58;
 extern void func_80015978(s32, s32*);
-extern void func_8012E5CC(s32, u16, u16);
+extern s32 func_8012E5CC(s32, s32, s32);
 extern void func_8002D4C8(s32 a0, s32 a1);
 
 void func_80147364(u16 param_1, u16 param_2) {
@@ -5942,7 +5942,7 @@ DEFINE_func_8014F3E8()  /* dedup: shared engine-core @0x8014F3E8 (src/shared) */
 
 
 
-extern void func_8014F4C0();
+extern s32 func_8014F4C0();
 
 s32 func_8014F468(void)
 {

src/ov_SC07_007/ov_SC07_007_jr_80140608.c

@@ -529,7 +529,7 @@ extern void func_80136C54(void);
 extern void func_80136D00(void);
 extern void SetLineG2(void *);
 extern void func_80136D08(s32 arg0, s32 arg1);
-extern u16 D_80126CC4;
+extern s16 D_80126CC4;
 extern M2C_UNK func_800153CC(M2C_UNK, u16, M2C_UNK, M2C_UNK, s32, s32);
 extern void func_80136DFC(void);
 extern void func_80136EC4(void);
@@ -5725,7 +5725,7 @@ DEFINE_func_8014F2E0()  /* dedup: shared engine-core @0x8014f2e0 (src/shared) */
 DEFINE_func_8014F3E8()  /* dedup: shared engine-core @0x8014F3E8 (src/shared) */
 
 
-extern void func_8014F4C0(u8 *a0);
+extern s32 func_8014F4C0();
 
 s32 func_8014F468(void)
 {

src/ov_SC07_010/ov_SC07_010_jr_80140608.c

@@ -4766,7 +4766,7 @@ DEFINE_func_8014F2E0()  /* dedup: shared engine-core @0x8014f2e0 (src/shared) */
 DEFINE_func_8014F3E8()  /* dedup: shared engine-core @0x8014F3E8 (src/shared) */
 
 
-extern void func_8014F4C0(u8 *a0);
+extern s32 func_8014F4C0();
 
 s32 func_8014F468(void)
 {

src/ov_SC07_011/ov_SC07_011_jr_80140608.c

@@ -529,7 +529,7 @@ extern void func_80136C54(void);
 extern void func_80136D00(void);
 extern void SetLineG2(void *);
 extern void func_80136D08(s32 arg0, s32 arg1);
-extern u16 D_80126CC4;
+extern s16 D_80126CC4;
 extern M2C_UNK func_800153CC(M2C_UNK, u16, M2C_UNK, M2C_UNK, s32, s32);
 extern void func_80136DFC(void);
 extern void func_80136EC4(void);
@@ -5727,7 +5727,7 @@ DEFINE_func_8014F2E0()  /* dedup: shared engine-core @0x8014f2e0 (src/shared) */
 DEFINE_func_8014F3E8()  /* dedup: shared engine-core @0x8014F3E8 (src/shared) */
 
 
-extern void func_8014F4C0(u8 *a0);
+extern s32 func_8014F4C0();
 
 s32 func_8014F468(void)
 {

src/shared/engine_core.h

@@ -20581,7 +20581,7 @@
     extern void func_80147324(s32 arg0); \
     extern s32 func_80146A6C(s32 a0, void *a1, s32 a2, s32 a3, s32 a4, s32 a5, s32 a6); \
     extern void func_80147364(); \
-    extern void func_80146C3C(void); \
+    extern void func_80146C3C(); \
     void func_8016A08C(s32 param_1) { \
         register s32 s0 __asm__("$16"); \
         register void *s1 __asm__("$17"); \
@@ -22406,7 +22406,7 @@
     extern u8 D_80078EBF; \
     extern void func_80147324(s32 arg0); \
     extern void func_80147364(); \
-    extern void func_80146C3C(void); \
+    extern void func_80146C3C(); \
     void func_8016A1CC(int param_1) \
     { \
         register int iVar1 __asm__("$2"); \