Clarify CallWaveKit licensing for 0.4.1

[PetrShtuka]

Summary

• add a component-level LICENSING.md that separates the MIT CallWaveKit source from the GPL-2.0-or-later public PJSIP binary
• preserve the earlier MIT copyright notice and add Copyright (c) 2026 Petr Shtuka
• declare MIT AND GPL-2.0-or-later in the CocoaPods metadata and bump the package to 0.4.1
• update README, security, changelog and release instructions with the same terminology

Why

The 0.4.0 podspec declared only MIT even though the distribution also contains a separately licensed PJSIP binary. That could incorrectly suggest that the MIT licence covers the entire binary distribution. The new notice makes clear that installing CallWaveKit does not grant or transfer a proprietary PJSIP licence.

Impact

There are no runtime, public API or binary changes. Open-source consumers receive clearer GPL compliance information; closed-source consumers are directed to obtain an appropriate alternative PJSIP licence directly from Teluu.

Validation

• 67 tests pass
• pod ipc spec resolves version 0.4.1 and the combined licence metadata
• pod lib lint CallWaveKit.podspec --skip-tests --platforms=ios passes without --allow-warnings
• git diff --check passes