feat: add --publish flag to connect upload command

[lee-reinhardt]

Summary

• adds --publish flag to avocado connect upload that publishes the runtime immediately after upload (draft → published)
• adds publish_runtime() method to ConnectClient — calls PUT /api/.../runtimes/:id with {"runtime": {"status": "published"}}
• publish runs after upload completion but before any --deploy-* processing
• works in both the normal upload path and the "already draft" dedup path

Usage

# upload and publish
avocado connect upload dev --version dev-002 --publish

# full pipeline: upload, publish, deploy
avocado connect upload dev --version dev-002 --publish --deploy-cohort COHORT_ID --deploy-activate

Test plan

• avocado connect upload dev --version X --publish uploads and publishes in one step
• avocado connect upload dev --version X (no flag) still leaves runtime in draft
• re-running upload with --publish on an already-draft runtime publishes it
• --publish + --deploy-cohort + --deploy-activate chains correctly (publish before deploy)