Consider renaming use server to use actions

[PaulRBerg]

Goals

1. Reduce confusion between Server Components and Server Actions
2. Make the directive's purpose self-documenting
3. Align naming with the actual feature ("Server Actions")

Non-Goals

1. Changing the behavior of Server Actions
2. Modifying "use client" or other directives
3. Deprecating "use server" immediately (could coexist during transition)

Background

The "use server" directive is frequently misunderstood as the counterpart to "use client", leading developers to assume it means "this is a Server Component."

The server-only package adds to this confusion. Both contain the word "server," but they do opposite things:

• "use server" — enables client imports (exposes functions as callable RPCs)
• import "server-only" — forbids client imports (build fails if bundled)

Server Components have no directive—they're the default. "use server" exists solely to create Server Actions, but the name doesn't reflect this. Renaming it to "use actions" would.

Proposal

Rename "use server" to "use actions".

• Clearer intent: the directive creates callable actions, not "server components"
• Symmetry isn't always correct: "use client" and "use server" suggest false equivalence
• Migration path: support both directives temporarily, emit deprecation warning for "use server"

I'm not planning to contribute an implementation, but happy to help with documentation or further discussion.