Add Facebook Share and adopt master-only releases

[Kapusch]

What changed

• add selectable ShareKit/CoreKit bindings without adding LoginKit to Share-only consumers;
• package the required ShareKit, CoreKit, CoreKit Basics and FBAEMKit modules explicitly;
• reject LoginKit and GamingServicesKit from the Share-only package path;
• consolidate releases on master and require publishable commits/tags to be reachable from it;
• document repository structure, AI guidance, packaging, privacy manifests and release operations.

Why

BloomFly needs Facebook Feed sharing on iOS while Facebook Login remains out of scope. CoreKit 18.0.2 links FBAEMKit, so FBAEMKit is retained as a runtime dependency; it is not a login module. The single-branch policy also makes the old release/1.0.0 branch safely removable after merge.

Impact

The compatibility default remains Login-only. BloomFly can select Share and receive the audited native module set. No release branch or historical tag is rewritten by this PR.

Validation

• native iOS framework build completed;
• dotnet pack produced Kapusch.Facebook.iOS.1.1.0.nupkg;
• package modules, privacy manifests and checksums validated;
• BloomFly iOS source-consumer build and ATT audit passed;
• workflow YAML and repository guidance validated.