Add code-only deploy support

[Jaytee-fn]

The change adds deploy support for code-only functions.

This PR extends 'fn deploy' so that code-only functions can be deployed using either:

• direct archive source
• Object Storage-backed archive source

The deploy flow automatically builds the archive when needed and then creates or updates the target function using code-only source/runtime configuration.Earlier PRs introduce the underlying build, push, context, and create/update support that deploy depends on.

PR includes -

• detect 'code_only: true' during deploy
• add a dedicated code-only deploy path
• build the local archive automatically during deploy
• support direct archive deploy when no Object Storage target is configured
• support Object Storage-backed deploy when bucket/namespace are configured
• create or update the target function using code-only source/runtime fields

fn deploy --app --working-dir

when context has no Object Storage settings.
Expected:

• archive built automatically
• function created/updated using direct archive source

when context has:

• object_storage_bucket_name

• namespace
  Expected:

• archive built or reused

• object-storage source path used

• function created/updated successfully