feat: M6.40批 — 阅读器UI改版(书架list·grid+空态骨架+界面设置+App设置页+header·footer+背景黑默认) + 系统级音量翻页映射 + P1 MD3(select面板28/对话框按钮胶囊) + MeowPanel写端点护栏 + SDK公开仓·文档同步

- reader: app.c/shelf.c/reader.c 全套UI; 新增 reader_conf(reader.conf)/settings(App设置页)/reader_ipc(音量翻页IPC响应); app.json加volume_page
- launcher: keys.c meow_volpage_*门 + util.c app_id→fd映射(HELLO记fd/断开清) + app_launcher.c 前台三处接线(进入sink/按键路径volpage_key/离开clear) → 前台声明volume_page的App音量键→MSG_KEY_PAGEUP/PAGEDOWN翻页(非阅读器前台音量照旧)
- sdk: meow_select.c 底部面板28 + meow_ui_dialog.c 对话框按钮胶囊(h/2) + test_meow_ui_select.c修采样
- meowpanel: /api/net/policy·/api/power/policy 加防自锁+policy默认关两条护栏(panel.policy_enabled默认0)
- 文档: MEOW_APP_SDK.md §12.6 + meowpanel README端点表

0warning;宿主测试全过;二进制留批量批次未入库

patch_v2/meowpanel/src/mp.h

@@ -270,6 +270,7 @@ int ipc_pm_send(uint16_t req_type, const void *pl, uint32_t plen, uint16_t *rtyp
 int api_power_policy_get(int sock);
 int api_power_policy_set(int sock, const char *body, size_t body_len);
 int api_power_window(int sock, uint16_t req_type, uint16_t want_type, const char *unavail);
+int power_policy_append_flag(sbuf_t *out, const char *obj);   /* 拼 guard③ policy_write_enabled 顶层键（自校验） */
 int api_power_history(int sock);
 int api_power_events(int sock);
 const char *ams_bin(void);
@@ -287,6 +288,8 @@ int api_net_ifaces(int sock);
 void net_policy_parse(const char *txt, sbuf_t *s);
 int api_net_policy_get(int sock);
 int api_net_policy_set(int sock, const char *body, size_t body_len);
+int net_locked_entity(const char *entity);           /* 防自锁：系统关键网络/服务组件（dropbear/wpa_supplicant/udhcpc/netmgrd/svcd/sysui/init） */
+int panel_policy_write_enabled(void);               /* policy 默认关 gate：settings.conf `panel.policy_enabled`，缺省 0=关（只读透传） */
 void panel_strip_ansi(char *s);
 int txt_tokens(char *buf, char **toks, int maxtoks);
 void join_tokens(char **toks, int from, int to, char *out, size_t cap);