fix(sched): 内联汇编改用 lea + 间接寻址，绕开 [rip + sym + 偏移] 不被集成汇编器接受

llc 集成汇编器对 mov qword ptr [rip + _isr_scratch + 8], rcx 这种'RIP 相对符号 + 常量偏移'的直接寻址报 invalid operand（把整条指令识别成缺源操作数）。改为先 lea rsi, [rip + _isr_scratch]（lea 形式此前已验证可用），再按 [rsi + N] / [rdx + N] 访问，共 12 处（保存 6 + 恢复 6）。rsi/rdx 都在 _do_switch 的 push 列表内，切栈后写入会被随后的 pop 恢复，不影响新线程寄存器。

VKernel/Kernel/sched/sched.vp

@@ -340,21 +340,22 @@ def _do_switch():
             mov rax, qword ptr [rip + _switch_old_fpu]
             fxsave [rax]
             # 按线程保存 ISR scratch（被抢占的 ISR 会跨越其它线程的 ISR）
+            lea rsi, [rip + _isr_scratch]
             mov eax, dword ptr [rip + _switch_old_tid]
             imul rax, rax, 48
             lea rdx, [rip + _isr_scratch_tbl]
             add rdx, rax
-            mov rcx, qword ptr [rip + _isr_scratch]
+            mov rcx, qword ptr [rsi]
             mov qword ptr [rdx], rcx
-            mov rcx, qword ptr [rip + _isr_scratch + 8]
+            mov rcx, qword ptr [rsi + 8]
             mov qword ptr [rdx + 8], rcx
-            mov rcx, qword ptr [rip + _isr_scratch + 16]
+            mov rcx, qword ptr [rsi + 16]
             mov qword ptr [rdx + 16], rcx
-            mov rcx, qword ptr [rip + _isr_scratch + 24]
+            mov rcx, qword ptr [rsi + 24]
             mov qword ptr [rdx + 24], rcx
-            mov rcx, qword ptr [rip + _isr_scratch + 32]
+            mov rcx, qword ptr [rsi + 32]
             mov qword ptr [rdx + 32], rcx
-            mov rcx, qword ptr [rip + _isr_scratch + 40]
+            mov rcx, qword ptr [rsi + 40]
             mov qword ptr [rdx + 40], rcx
             mov rax, qword ptr [rip + _switch_old_rsp]
             mov qword ptr [rax], rsp
@@ -364,22 +365,23 @@ def _do_switch():
             mov rax, qword ptr [rip + _switch_new_fpu]
             fxrstor [rax]
             # 恢复切入线程的 scratch（不在 ISR 中时内容无意义，覆盖无害）
+            lea rsi, [rip + _isr_scratch]
             mov eax, dword ptr [rip + _switch_new_tid]
             imul rax, rax, 48
             lea rdx, [rip + _isr_scratch_tbl]
             add rdx, rax
             mov rcx, qword ptr [rdx]
-            mov qword ptr [rip + _isr_scratch], rcx
+            mov qword ptr [rsi], rcx
             mov rcx, qword ptr [rdx + 8]
-            mov qword ptr [rip + _isr_scratch + 8], rcx
+            mov qword ptr [rsi + 8], rcx
             mov rcx, qword ptr [rdx + 16]
-            mov qword ptr [rip + _isr_scratch + 16], rcx
+            mov qword ptr [rsi + 16], rcx
             mov rcx, qword ptr [rdx + 24]
-            mov qword ptr [rip + _isr_scratch + 24], rcx
+            mov qword ptr [rsi + 24], rcx
             mov rcx, qword ptr [rdx + 32]
-            mov qword ptr [rip + _isr_scratch + 32], rcx
+            mov qword ptr [rsi + 32], rcx
             mov rcx, qword ptr [rdx + 40]
-            mov qword ptr [rip + _isr_scratch + 40], rcx
+            mov qword ptr [rsi + 40], rcx
             popfq
             pop r15
             pop r14