fix(ucm): use top-level SectionDevice in HiFi.conf for ALSA parser

Nested SectionVerb caused alsaucm "no use case device defined", so PipeWire
never exposed the HiFi profile. Document alsaucm check and reinstall path.

Made-with: Cursor

docs/linux-hdmi/OPERATION_PipeWire_Kaisa_HDMI.md

@@ -112,6 +112,14 @@ pactl list short sinks
 pactl set-card-profile "$(pactl list cards short | awk '/cml_rt5682/ {print $2; exit}')" HiFi
 ```
 
+**若 `pactl set-card-profile … HiFi` 报「无此实体」**：多半是 **UCM 未成功加载**（WirePlumber 因此注册不出 `HiFi` profile）。先在终端验证 ALSA 能否解析配置：
+
+```bash
+alsaucm -c sof-rt5682 list _verbs
+```
+
+若出现 **`parse_verb_file` / `no use case device defined`** 等，说明 **`HiFi.conf` 结构不符合 UCM2 要求**（已修正为「顶层 `SectionDevice`」写法）；请 **`git pull`** 后重新执行 **`./scripts/install-kaisa-ucm-overlay.sh`**，再 **`systemctl --user restart wireplumber pipewire pipewire-pulse`**。
+
 **安装（在仓库根目录，需 sudo）**：
 
 ```bash