Release PocketStation Relay connector 0.1.2

[Raphjacksun7]

What changed

• Carries PocketStation output generation ownership through packetization and
  Opus encoding, then discards cancelled output before RTP publication.
• Requires the released PocketStation Core 1.1.3 crate.
• Removes sibling Core paths from runtime and conformance dependencies.
• Adds public, packaged 0.1.2 release notes with the receiver-playout boundary
  and upgrade command.

User impact

Generated audio cancelled after an interruption no longer remains in the Relay
Connector's bounded pre-RTP queue. Other AudioBuses continue. RTP already sent
to Relay and receiver-buffered audio still require destination playout control.

This is a compatible 0.1.x update with no Connector configuration migration.

Validation

• 33 package tests pass.
• Portable Connector semantics pass.
• Strict Clippy passes with warnings denied.
• The committed crate archive rebuilds against crates.io PocketStation 1.1.3.
• Cargo publish dry run passes with 22 packaged files and no sibling path.

Remaining limits

This release does not add TURN allocation, receiver playback control, or
cross-network qualification.