fix(src): ov_SC04_018_jr_8017AE2C.c — restore func_8017E7CC's region to its last-GREEN form (commit:2628) + a block-scope extern for D_801B9AA8

The 08-25 maintenance revert/restore cycle left the TU uncompilable under the TU-alone/rtu view,
which the resolver billed to 39 separate drafts as 'undeclared'. File-scope declaration is closed
off by the TU's own §63 block-scope convention (later functions declare the symbol with other
types), so the decl lives inside the function; the use is address-only, hence byte-neutral. The
real build's pads drift ('consumed 3 but 4 pad specs') is unchanged and remains the open repair
for this binary (stays on .run/baseline_red.txt).

src/ov_SC04_018/ov_SC04_018_jr_8017AE2C.c

@@ -4819,7 +4819,6 @@ extern void func_8012A828(s32 *a0, s32 a1);
     }
 
 
-extern s32 D_801B9AA8;
 void func_8017E7CC(int param_1)
 {
     *(short *)(param_1 + 3) = 2;
@@ -4910,6 +4909,7 @@ void func_8017EBA0(s32 a0) {
 
 
 
+extern void func_8017E7CC(void);
     void func_8017EBE0(u8 *a0) {
         if (*(u16 *)((s32)a0 + 0x34) == 1) {
             func_8017E7CC();