Add Transloadit transcription skill

[kvz]

Summary

• add transform-transcribe-audio-with-transloadit for one-off local audio/video transcription
• route agents through the new @transloadit/node speech transcribe intent from Add speech transcribe intent node-sdk#419
• document Replicate as the current default provider while ElevenLabs Scribe is still pending, and avoid the WIP transloadit provider
• expose the new skill from the Transloadit router skill and README examples

Tests

• yarn lint:js
• npx -y skills add ./skills --list
• git diff --check

Notes

This should land after, or alongside, transloadit/node-sdk#419 so the documented speech transcribe intent exists in the published CLI.