refactor(whatsrust): extract outbound message wrappers

[Andiveli]

Summary

• Move outbound send and forward wrappers into message_send.rs.
• Preserve public signatures, FFI behavior, ownership, quote handling, and send policy.

Changes

• Moved send_message, send_text_message, and forward_message from the facade.

Chain Context

• Start: PR refactor(whatsrust): extract message payload builders #321 (refactor/whatsrust-message-payload-builders-v2).
• End: outbound wrappers isolated; contacts and communities are the immediate child.
• Diagram: refactor(whatsrust): extract action wrappers #315 -> refactor(whatsrust): extract read synchronization wrappers #317 -> refactor(whatsrust): extract message payload builders #321 -> 📍 this PR -> contacts/communities -> remaining queries -> facade cleanup.

Testing

• cargo fmt --all -- --check
• CARGO_TARGET_DIR=/home/samael/Escritorio/public/wptui-public/target cargo check --workspace --all-targets
• CARGO_TARGET_DIR=/home/samael/Escritorio/public/wptui-public/target cargo test -p whatsrust message_send::tests -- --test-threads=1
• git diff --check

Review Budget and Rollback

• Authored diff: 256 lines (128 additions + 128 deletions).
• Rollback: revert commit 94f66a2.

Closes #320