docs(faq): add CLI namespace-not-found and PostgreSQL permission entries (#743)

Add two entries collected from community support, to both the zh docs and
the en i18n mirror:

- FAQ: installing a skill via CLI reporting `namespace not found` — set the
  registry / log in with an API token, and use the correct namespace slug
  (`@team/skill` -> `team--skill`); the web UI Install button provides a
  ready-made command.
- Troubleshooting: PostgreSQL container failing to start with
  `operation not permitted` on bind mounts — fix data volume ownership
  (`chown 999:999`), check SELinux, or use the `runtime.sh` script.

Signed-off-by: FenjuFu <92919259+FenjuFu@users.noreply.github.com>

document/docs/05-reference/faq.md

@@ -34,6 +34,17 @@ description: 常见问题解答
 3. 是否包含必需的 SKILL.md
 4. SKILL.md frontmatter 格式是否正确
 
+### 使用 CLI 安装技能时报 `namespace not found`？
+
+多数情况是 CLI 没有指向你自己的 SkillHub 实例，或命名空间格式不对：
+
+1. **配置 registry 并登录**：用环境变量或 `--registry` 指向你的实例，例如
+   `clawhub --registry https://skillhub.your-company.com install <skill>`；登录需要先在 Web 控制台生成 API Token。
+2. **命名空间 slug 格式**：全局命名空间的技能直接用名字（如 `my-skill`）；团队命名空间要用 `team--skill` 的形式（`@team/skill` → `team--skill`）。
+3. 最稳妥的方式是直接在 SkillHub Web 界面点技能的「安装」按钮，复制其中已经带好正确 registry 与命名空间的命令。
+
+> SkillHub 同时提供 `clawhub` 和 `skillhub` 两种 CLI，用法见各自 README；通过 OpenClaw 对话安装技能时，底层同样调用 CLI。
+
 ## 开发相关
 
 ### 如何扩展 OAuth Provider？

document/docs/05-reference/troubleshooting.md

@@ -22,6 +22,14 @@ description: 常见问题诊断和解决方案
 - Redis 连接失败
 - 环境变量缺失
 
+### PostgreSQL 容器启动报 `operation not permitted`（写 `postmaster.pid` / `pg_wal` 失败）
+
+内网/自建环境使用绑定挂载时常见，根因是**数据卷目录权限**与容器内 `postgres` 用户（UID 999）不匹配：
+
+1. 将数据卷目录属主改为 postgres 用户：`chown -R 999:999 <数据目录>`。
+2. 在 RHEL/CentOS 上检查 SELinux 是否拦截了容器写入宿主目录。
+3. 推荐直接使用官方 `runtime.sh` 部署脚本，它会处理相关初始化步骤，避免手工编写 compose 时漏配权限。
+
 ## 上传失败
 
 ### 技能包上传失败

document/i18n/en/docusaurus-plugin-content-docs/current/05-reference/faq.md

@@ -34,6 +34,16 @@ Check:
 3. Whether required SKILL.md is included
 4. Whether SKILL.md frontmatter format is correct
 
+### CLI install reports `namespace not found`?
+
+Usually the CLI is not pointing at your own SkillHub instance, or the namespace format is wrong:
+
+1. **Set the registry and log in**: point at your instance via an environment variable or `--registry`, e.g. `clawhub --registry https://skillhub.your-company.com install <skill>`. Logging in requires an API Token generated in the web console first.
+2. **Namespace slug format**: skills in the global namespace use the bare name (e.g. `my-skill`); team namespaces use the `team--skill` form (`@team/skill` → `team--skill`).
+3. The most reliable way is to click the **Install** button on the skill's page in the SkillHub web UI and copy the command, which already includes the correct registry and namespace.
+
+> SkillHub ships both a `clawhub` and a `skillhub` CLI (see their respective READMEs); installing a skill through an OpenClaw conversation calls the CLI under the hood as well.
+
 ## Development Related
 
 ### How to extend OAuth Provider?

document/i18n/en/docusaurus-plugin-content-docs/current/05-reference/troubleshooting.md

@@ -22,6 +22,14 @@ description: Common problem diagnosis and solutions
 - Redis connection failed
 - Environment variables missing
 
+### PostgreSQL container fails to start with `operation not permitted` (cannot write `postmaster.pid` / `pg_wal`)
+
+Common in intranet / self-hosted environments using bind mounts. The root cause is a mismatch between the **data volume directory permissions** and the container's `postgres` user (UID 999):
+
+1. Change the data volume directory owner to the postgres user: `chown -R 999:999 <data-dir>`.
+2. On RHEL/CentOS, check whether SELinux is blocking the container from writing to the host directory.
+3. Prefer the official `runtime.sh` deployment script, which handles the relevant initialization steps and avoids permission gaps from hand-written compose files.
+
 ## Upload Failed
 
 ### Skill Package Upload Failed