nx_nishios_fb_x86.nx

nx_nishios_fb_x86.nx -- NishiOS GUI rung-7: the kernel draws the framebuffer with REAL x86 EXECUTION. Closes the seam I kept flagging: until now the desktop was drawn by nx_fb (a NishiLang driver) called AFTER boot. Here the booted kernel's draw is REAL x86 INSTRUCTIONS executed on the sovereign emu: an authored fill loop (mov-imm / store [rax],rcx / add / cmp / jne / syscall) writes a computed value into every framebuffer word. The emu runs it; afterward we read the framebuffer straight out of the emu's memory -- the pixels were written by x86 the CPU model executed, not by a NishiLang call. Then export to BMP via nx_fb (now ONLY the encoder, not the renderer). KAT: the framebuffer holds EXACTLY what the x86 loop computed (mem[fb+8*w] low byte == w&0xFF) at the start, middle and END of the loop (proving it ran to completion), clean exit, BMP exported. HONEST SCOPE: the loop fills a computed ramp (proves per-pixel x86 writes); richer desktop chrome drawn purely in x86 (rects/text via x86) is the continuation. No hw writes (Rule 26). expect_exit: 0 tier: ORIGINAL