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.
• Kept explicit facade availability through the existing module wiring.

Chain Context

• Start: PR refactor(whatsrust): extract message payload builders #321 (refactor/whatsrust-message-payload-builders-v2).
• End: outbound wrappers isolated; query extraction remains for later children.
• Diagram: refactor(whatsrust): extract action wrappers #315 -> refactor(whatsrust): extract read synchronization wrappers #317 -> refactor(whatsrust): extract message payload builders #321 -> 📍 this PR -> queries -> facade cleanup.
• Immediate parent: PR refactor(whatsrust): extract message payload builders #321.

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
• Manual runtime testing: not applicable; behavior-preserving FFI extraction.

Review Budget and Rollback

• Authored diff: 256 lines (128 additions + 128 deletions).
• Rollback: revert commit c1a5264 to restore wrappers to lib.rs.

Out of Scope

• No ABI, ownership, panic, send-policy, threading, or bug-fix changes.

Closes #320

[Andiveli]

Superseded by repaired replacement PR above; this branch was accidentally advanced with the next child and is closed without rewriting history.