docs(kaisa): make UCM HiFi the only supported path

Promote UCM2/HiFi (Jack-driven) as the primary delivery, add HISTORY.md,
remove ProAudio/REPRO docs and non-UCM scripts, and fix repo-wide references.

Made-with: Cursor

docs/linux-hdmi/systemd-user/kaisa-pro-audio-reapply.service

@@ -1,26 +0,0 @@
-# 登录会话：在 pipewire-pulse 就绪后延迟重施 pro-audio，缓解「启动后出现一下又消失」
-# （多为 GNOME/会话稍晚把卡改回 HiFi 或 stereo-fallback）。
-#
-# 安装（示例：脚本放到 ~/.local/bin，避免 unit 里写死仓库路径）：
-#   mkdir -p ~/.local/bin
-#   ln -sf /path/to/chromebox_10th_audio_driver/scripts/kaisa-reapply-pro-audio-session.sh ~/.local/bin/
-#   mkdir -p ~/.config/systemd/user
-#   cp docs/linux-hdmi/systemd-user/kaisa-pro-audio-reapply.service ~/.config/systemd/user/
-#   systemctl --user daemon-reload
-#   systemctl --user enable --now kaisa-pro-audio-reapply.service
-#
-# 与仓库示例 kaisa-hdmi-iec958-pipewire.service 二选一即可；本 unit 自带可执行路径（~/.local/bin）。
-
-[Unit]
-Description=Kaisa: re-apply PipeWire pro-audio after login (mitigate profile revert)
-After=pipewire-pulse.service
-Wants=pipewire-pulse.service
-
-[Service]
-Type=oneshot
-RemainAfterExit=yes
-ExecStartPre=/bin/sleep 2
-ExecStart=%h/.local/bin/kaisa-reapply-pro-audio-session.sh
-
-[Install]
-WantedBy=default.target