fix(dsk,firstInit,build): let the system boot all the way to the desktop

Four independent blockers sat between "the image boots UTSM" and "the desktop
comes up". Each one wedged the boot on its own; all four are fixed here and the
tree now reaches "[desktop] desktop ready" under QEMU/OVMF
(evidence: .build_tmp/d2.log).

1. FirstInit made networking a hard gate (CODE/firstInit/main.c)
   The setup wizard always showed the network page, and on a machine with no
   wireless device the only exit was Save - pressing Connect raised NET-E01.
   Networking is not a precondition for entering the system, so a wizard that
   cannot be completed without it is a plain design defect.
   - No wireless device detected -> skip the network page entirely (the
     g_no_wireless_device flag already existed but was only logged).
   - With a device present, add a Skip button (draw + mouse hit-box + keyboard
     Enter), mirroring "I don't have internet" on Windows.
   - Connect keeps its zero-fallback NET-E01 panic: the unimplemented path is
     still honest, it just no longer holds the user hostage.

2. ESP cluster size left no room in the root directory
   (CODE/linux/pack_system_image.sh)
   With the cluster size left to mkfs it chose 1 sector, i.e. 16 directory
   entries per cluster. The ESP root ends up holding exactly 16 entries
   (DESHABBOOT/EFI/LIMINE/BOOT/DRIVER/SYSTEM/USER/NVVARS plus one long-name
   entry each), and the root chain is a single cluster - so on first boot the
   DSK could never write USER.CONF.
   Pin -s 4 (2KiB, 64 entries): it clears the FAT32 65525 lower bound and the
   0xFFF5 boundary that -s 8 lands on at this 256MiB size, and leaves 48 free
   entries. The alternatives were measured, not guessed (see the comment).

3. DSK could not grow the root directory (CODE/dsk/main.c)
   fat32_write_root_file returned -4 "no free dir entry" whenever the scan of
   the root chain came up empty. A FAT filesystem is supposed to extend the
   directory chain, so allocate a cluster, link it at the current tail, write
   the entry there and commit the FAT. Fixing only (2) would have papered over
   this: any real disk whose root fills up would still fail the same way.

4. Nothing generated the CJK bitmap font packs (build.ps1)
   The desktop loads system/font/simhei_16.dbf and panics DESK-E04 FONT PACK
   MISSING without it. The .dbf files are generated from simhei.ttf by
   CODE/font/mkfont.py and are gitignored, but no build step ever invoked it -
   same class of bug as the previously untracked .drv binaries. Generate
   simhei_16.dbf / simhei_24.dbf in build.ps1 (with the existing WSL python3
   fallback for Pillow), rebuilding only when the TTF is newer than the pack.

docs/STATUS.md updated to match: FirstInit wizard and the D3 named API export
table move to done, and the FAT32 / ESP cluster size / CJK font pack entries
are added or corrected. D3 was already fully implemented (table, lookup,
selftest with positive and negative cases, TST-E21..E24 instrumentation) -
only the status row was stale.

Verified boot chain (QEMU/OVMF, dev variant):
  BdsDxe -> Limine -> UTSM -> DKM 17/17 -> DSK -> FirstInit (network page
  skipped) -> USER.CONF written -> login (password accepted) -> desktop:
  "[zhfont] dbf loaded (16px ok)" ... "[desktop] desktop ready"

docs/STATUS.md

@@ -44,7 +44,7 @@
 | e1000 | ✅ | RX/TX + DHCP/ARP/UDP/DNS（polling） | — |
 | virtio_net | ✅ | legacy split-ring virtqueue（desc/avail/used）+ vq_setup + 32×2048B RX 缓冲 + TX/RX 环 + DHCP DISCOVER→OFFER selftest；VNET-E01/E02 零降级插桩。无设备时 WARN 后正常 ready（设计内回退） | `CODE/DKM/virtio_net/virtio_net.c`；未挂设备时串口 `[virtio_net] virtio-net device not found` → `driver ready` |
 | 热卸载（D1） | ⬜ | 仅有 NO_UNLOAD 标志与状态机文档 | — |
-| 按名 API 导出表（D3） | ⬜ | 固定偏移 struct ABI | `CODE/sdk/include/deshab/kernel_api.h` |
+| 按名 API 导出表（D3） | ✅ | `dkm_kapi_table`（magic/version/count/entries/lookup）挂在 `kernel_api->kapi` 尾部（ABI 兼容追加）；14 条按名导出（log.*/dma.alloc_pages/irq.register/irq.vector_*/mm.map_mmio/mm.unmap_mmio/apic.register_eoi/drr.*/utrw.debug_dump）；selftest 含正例调用 + 未命中负例 + TST-E21..E24 插桩 | `CODE/UTSM/dkm/kernel_api.c` + `test/utsm_selftest.c`（需 FUCK `[boot] selftest=2` 才执行该段） |
 | 彩色日志（D4） | ✅ | `dkm_log_set_driver`（驱动名 FNV hash → 8 色调色板，确定可复现）；init 期间驱动日志带 ANSI 色（仅串口，BOOTLOG 纯文本）；FUCK `[debug] color_log` 总开关 | `.build_tmp/qemu_serial_d4color.log`（1150 彩色行） |
 
 ## DSK 主内核 / 用户态
@@ -52,7 +52,7 @@
 | 子系统 | 状态 | 边界/说明 | 证据 |
 |--------|------|----------|------|
 | 启动 Logo（静态莲花） | ✅ | 旋转加载环已移除 | QEMU 现象 |
-| FirstInit 向导 | 🔶 | 输入+SHA256+写盘闭环；按键崩溃未复现（B6） | `.build_tmp/qemu_serial_b6.log` |
+| FirstInit 向导 | ✅ | 输入+SHA256+写盘闭环；**联网不是进系统的前置条件**：检测到无无线设备直接跳过网络页，有设备时提供 Skip 按钮（渲染+鼠标+键盘三路），Connect 仍为零降级 NET-E01 panic | `.build_tmp/d2.log`（`no wireless device; skipping network setup page` → `USER.CONF` → login → desktop）|
 | 可跳过 FirstInit（F5） | ✅ | `[dsk] skip_firstinit=1` 直达 desktop，跳过向导与登录 | `.build_tmp/qemu_serial_f1f4f5.log` |
 | mouseInit（PS/2 鼠标） | ✅ | IRQ12 + 包解码 + 光标（M1） | `.build_tmp/qemu_serial_mouse.log` |
 | desktop.elf | ✅ | 三页面+窗口+任务栏+双缓冲；打字机效果已删（整屏一次绘制）；DSK-E01 fatal 插桩 | — |
@@ -81,7 +81,9 @@
 | 项 | 状态 | 说明 | 证据 |
 |----|------|------|------|
 | ext4 读写驱动（CODE/dsk/ext4.c） | ✅ | GPT 定位 p2 + feature 校验 + extent 树(depth0/1)读写 + 块/inode 分配回收 + 目录项插入 + 写后回读校验；启动自检 PASS | `.build_tmp/qemu_run.log`（[EXT4] selftest PASS） |
-| FAT32 大盘写修复 | ✅ | 按需 FAT 表项 RMW（fat32_fat_read/write_entry）+ 块状空闲簇扫描（fat32_find_free_cluster）；修复 rec_len +4 收缩偏移与 chunk 对齐两处错位 | 同上（USER.CONF verify ok → firstInit.txt flip ok） |
+| FAT32 大盘写修复 | ✅ | 按需 FAT 表项 RMW（fat32_fat_read/write_entry）+ 块状空闲簇扫描（fat32_find_free_cluster）；修复 rec_len +4 收缩偏移与 chunk 对齐两处错位；**根目录链满时自动扩展**（分配新簇挂链尾后写条目，不再直接 `-4` no free dir entry）| 同上（USER.CONF verify ok → firstInit.txt flip ok）|
+| ESP 簇大小（打包侧） | ✅ | `-s 4`（2KiB 簇 / 64 目录项）固定：避开 `spc=8` 的 65535 簇 OVMF 拒绝边界，也避开 `spc=16` 的 FAT32 下限，同时给 ESP 根目录留出 64 项余量（`spc=1` 只有 16 项，打包内容正好塞满导致首次启动写 USER.CONF 必失败）| `CODE/linux/pack_system_image.sh`；`.build_tmp/d2.log` |
+| 中文字体位图字库（.dbf） | ✅ | `build.ps1` 调用 `CODE/font/mkfont.py` 由 `simhei.ttf` 生成 `simhei_16.dbf` / `simhei_24.dbf`（GB2312+ASCII）；此前无人生成，桌面必 panic DESK-E04 FONT PACK MISSING | `.build_tmp/d2.log`（`[zhfont] dbf loaded (16px ok)` → `desktop ready`）|
 | FS-E01..E07 / FS-E2x / FS-E3x 插桩 | ✅ | 写失败/校验不符/feature 不支持/路径缺失 → 莲花 panic 零降级 | `.build_tmp/qemu_run.log`（FS-E02/E06/E22 复现） |
 | 向导后强制重登 | ✅ | first-boot 分支 FirstInit→persist→login；登录跳过/失败 → FS-E06 panic | 同上（login success → desktop ready） |
 | NET-E01 网络页 Connect panic | ✅ | 无 wlan 栈，Connect 即 panic；Save(仅存配置) 为唯一前进路径 | 同上（NET-E01 复现，fb pmemsave 确认莲花屏） |