Merge branch 'docs/update_bt_common_homepage' into 'master'

docs: Add intro and brief descriptions to Bluetooth Common API home page

Closes DOC-11910

See merge request espressif/esp-idf!42582

docs/en/api-reference/bluetooth/bt_common.rst

@@ -1,9 +1,35 @@
-Bluetooth® Common
-=================
+Bluetooth\ :sup:`®` Common
+===============================
+
+:link_to_translation:`zh_CN:[中文]`
+
+**Bluetooth Common** provides shared definitions and APIs used by both Bluetooth Classic and Bluetooth Low Energy (Bluetooth LE). It serves as a foundation for shared functionality across Bluetooth components, offering unified interfaces for Bluetooth initialization, configuration, and device management.
+
+The Bluetooth Common API is organized into the following parts:
 
 .. toctree::
-   :caption: Bluetooth Common Defines and APIs
+   :maxdepth: 1
 
    Bluetooth Define <esp_bt_defs>
+
+Provides shared definitions and data structures used by both Bluetooth Classic and Bluetooth LE.
+
+.. toctree::
+   :maxdepth: 1
+
    Bluetooth Main <esp_bt_main>
+
+Provides core APIs for initializing, enabling/disabling, and managing the Bluetooth stack.
+
+.. toctree::
+   :maxdepth: 1
+
    Bluetooth Device <esp_bt_device>
+
+Provides APIs for managing device-level properties such as address, name, visibility, and coexistence settings.
+
+Each part typically includes the following sections:
+
+- **Overview**: Summary of purpose, key functionality, and main interfaces
+- **Application Examples**: Example projects demonstrating typical usage
+- **API Reference**: Detailed API documentation, including header files, functions, structures, macros, type definitions, and enumerations