fix: repair StackChan voice assistant intercom external component

[pfefferle]

Summary

Repairs common/stackchan-voice-assistant-base.yaml so it compiles against the current n-IA-hane/esphome-intercom component. The file was written for the old @v3.1.0 API; three changes bring it up to date. Confirmed validating with ESPHome 2026.5.3.

1. Broken git ref

The intercom repo switched to date-based tags and removed v3.1.0:

INFO Fetching v3.1.0
  couldn't find remote ref v3.1.0.

Pinned to v2026.5.0 (matches the ESPHome 2026.5.x line). Available upstream tags: v2026.5.0, v2026.6.0, v2026.6.1, v2026.6.2.

2. Missing audio_processor import

esp_aec declares AUTO_LOAD = ["audio_processor"]; an auto-loaded external component must be listed explicitly or ESPHome looks for a built-in and fails:

Unable to import component audio_processor: No module named 'esphome.components.audio_processor'

Added it to the import: components: [i2s_audio_duplex, esp_aec, audio_processor].

3. aec_id → processor_id

i2s_audio_duplex renamed its AEC attachment option to processor_id (cv.use_id(AudioProcessor)):

[aec_id] is an invalid option for [i2s_audio_duplex].

esp_aec is an AudioProcessor, so it's now wired via processor_id: aec.

Test plan

• Reproduced all three failures, fixed sequentially, and confirmed the config validates with ESPHome 2026.5.3.
• Verified v2026.5.0 exists via git ls-remote --tags.
• Confirmed esp_aec/__init__.py has AUTO_LOAD = ["audio_processor"] and i2s_audio_duplex accepts processor_id (not aec_id).
• The esp_aec, microphone (pre_aec), and speaker blocks validate unchanged against v2026.5.0.

Fixes #92

[pboushy]

I pinned intercom initially.
I tested the package in this branch and have confirmed it works on my StackChan with the following YAML:

substitutions:
  name: stackchan-voice-e29aa0
  friendly_name: StackChan Voice Assistant e29aa0

esphome:
  name: ${name}
  name_add_mac_suffix: false
  friendly_name: ${friendly_name}
api:
  encryption:
    key: !secret stackchan_voice_e29aa0__encryption_key
wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

packages:
  m5stack.stackchan-voice-assistant: github://pfefferle/m5stack-esphome-yaml/common/stackchan-voice-assistant-base.yaml@fix/intercom-ref-v2026.5.0

micro_wake_word:
  models:
    - model: github://TaterTotterson/microWakeWords/microWakeWordsV2/cor_taan_uh.json@main
    - model: github://TaterTotterson/microWakeWords/microWakeWords/hey_sarah.json@main