docs(irc): recommend self-hosted server examples

[zzz163519]

Summary

• replace Libera.Chat IRC setup examples with localhost/self-hosted ircd examples
• update setup prompt and env metadata to recommend a local/self-hosted IRC server
• add a regression test that keeps user-facing IRC recommendations from pointing back to Libera.Chat

Fixes #61181

Tests

• uv run --extra dev python -m pytest tests/gateway/test_irc_recommendations.py tests/gateway/test_irc_adapter.py tests/hermes_cli/test_setup_irc.py -q
• uv run --extra dev python -m ruff check plugins/platforms/irc/adapter.py hermes_cli/config.py tests/gateway/test_irc_recommendations.py
• git diff --check

[alt-glitch]

This was generated by AI during triage.

Duplicate of #61194 — both replace the Libera.Chat IRC setup examples with neutral/self-hosted ircd guidance for the same issue #61181, editing the same plugins/platforms/irc/ adapter/plugin.yaml + hermes_cli/config.py + docs. #61194 is the earliest-open canonical (created ~15.5h earlier). Maintainer picks one.

[zzz163519]

Closing in favor of the earlier canonical documentation fix in #61194.