Add mDNS dep and handle IPv4-only mDNS addr

[jb1228]

Add mdns to the component private requirements so mDNS symbols are available at build time. In connection_handler.c add a conditional to read the IPv4 address from the mdns result when IPv6 is disabled, falling back to ip_addr_copy for dual-stack builds. This avoids accessing IPv6 fields when LWIP IPv6 support is turned off.

[Copilot]

Pull request overview

This PR updates the snapclient component to ensure mDNS-related code builds correctly across LWIP IPv4/IPv6 configurations, particularly avoiding IPv6 field access in IPv4-only builds.

Changes:

• Adds the mdns component to snapclient private requirements.
• Adjusts mDNS result IP extraction in connection_handler.c to handle IPv4-only LWIP builds without touching IPv6 fields.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
components/snapclient/connection_handler.c	Adds an IPv4-only compile-time branch for extracting the remote IP from an mDNS result.
components/snapclient/CMakeLists.txt	Adds mdns to PRIV_REQUIRES so the component links mDNS symbols.

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[Copilot]

In the IPv4-only build branch, remote_ip is populated from re->addr->addr.u_addr.ip4 unconditionally. If CONFIG_SNAPCLIENT_CONNECT_IPV6 is enabled (Kconfig currently doesn’t prevent it when CONFIG_LWIP_IPV6 is off), the selection loop can break on a V6 address and this assignment will read the IPv4 field from a V6 address, producing an invalid remote IP. Consider forcing IPv4 selection when !CONFIG_LWIP_IPV6 (ignore CONFIG_SNAPCLIENT_CONNECT_IPV6 in that case) and/or assert/check the selected address type is V4 before assigning remote_ip in this branch.

[Copilot]

mdns is now listed in PRIV_REQUIRES unconditionally, but this component already adds it conditionally via idf_component_optional_requires(PRIVATE mdns) under if(CONFIG_SNAPSERVER_USE_MDNS). Keeping the dependency unconditional (and duplicated) will build/link the mdns component even when mDNS is disabled. Consider removing mdns from PRIV_REQUIRES and relying on the existing conditional idf_component_optional_requires, or otherwise make the dependency consistently conditional in one place.

Suggested change

	PRIV_REQUIRES esp_timer mdns opus flac lightsnapcast
	PRIV_REQUIRES esp_timer opus flac lightsnapcast

[luar123]

No idea why it is not working without this.

[jb1228]

These edits may not be necessary if the build flags are set properly in the ESPHome snapclient component. I can investigate further.

[luar123]

Thanks