DRV-32: Add Media Player entity support with Generic Media Player proxy

[svc-finitelabs]

Fixes DRV-32

Summary

Replaces the previous variables + device actions approach (PR #38, now closed) with a proper sub-driver using the SnapOne Generic Media Player proxy, per Derek's feedback to investigate the MSP proxy.

Entity module (src/esphome/entities/media_player.lua)

• Follows the same pattern as fan.lua, light.lua, lock.lua
• Dynamic binding discovery with ESPHOME_MEDIA_PLAYER class
• Proxy command forwarding via ENTITY_COMMAND
• State updates via UPDATE_STATE notification to sub-driver

Sub-driver (drivers/esphome_media_player/)

• Generic Media Player proxy on binding 5001
• Transport commands: PLAY, PAUSE, STOP, PLAYPAUSE
• ESPHome state → C4 play status mapping:
  • IDLE/NONE/OFF → stopped
  • PLAYING/ANNOUNCING/ON → playing
  • PAUSED → paused
• PLAY_STATUS_CHANGED notifications for native C4 UI
• ONLINE_STATUS_CHANGED for connection tracking
• Volume and mute state tracking from ESPHome
• Full documentation in www/documentation/index.md

Other changes

• Registered MediaPlayerEntity in main driver entity table
• Updated README: entity support table, bindings table, setup instructions
• Updated CHANGELOG

Build

Both drivercentral and oss distributions build cleanly (esphome_media_player.c4z in both).

[derek-miller]

Can you recommend any esphome devices with this entity? Or a way to build a mock one? I need something to test this with.

[svc-finitelabs]

Good question — ESPHome's media player support is pretty focused on ESP32 boards with I²S audio output. Here are your options:

Physical devices with media_player support:

• ESP32 + I²S DAC board (cheapest/easiest) — an ESP32 dev board wired to an external DAC like a MAX98357A, UDA1334A, NS4168, or PCM5102A. These are ~$3-5 breakout boards. Wire DOUT/BCLK/LRCLK to the DAC and you have a working media player that can play HTTP streams. The ESP32 internal DAC also works but sounds terrible.
• ESP32-S3-BOX / ESP32-S3-BOX-3 — Espressif's dev kits with built-in speaker and mic. Natively supported as media players in ESPHome. Probably the most turnkey option if you want something that just works out of the box.
• M5Stack Atom Echo / M5Stack NSP32 — compact ESP32 devices with built-in I²S audio output. Supported by ESPHome as media players.

Mock/virtual approach:

ESPHome doesn't have a "virtual" media player platform, but you could build a minimal mock pretty easily:

1. Flash an ESP32 dev board (~$5) with just the i2s_audio media player config — you don't even need a DAC connected. The entity will still register and report state changes, volume, mute, etc. It just won't produce audio without a DAC.
2. The minimal config would be something like:

esphome:
  name: media-player-test

esp32:
  board: esp32dev

i2s_audio:
  i2s_lrclk_pin: GPIO25
  i2s_bclk_pin: GPIO26

media_player:
  - platform: i2s_audio
    name: "Test Media Player"
    dac_type: external
    i2s_dout_pin: GPIO22
    mode: mono

The cheapest path for real testing would be an ESP32 dev board + MAX98357A breakout ($8 total). The ESP32-S3-BOX-3 is the nicest all-in-one option ($45) if you want something more polished.

For just validating the driver's state handling and proxy commands, a bare ESP32 with the I²S config (no physical DAC) should be sufficient since the entity will still report state transitions over the native API.