docs(getting-started,kernel): name which plugin artifact each scaffolder page means (#16484)

The docs-drift bot named three hand-written pages this change touches. Two of
them still carried the collision this card exists to remove.

`content/docs/getting-started/your-first-project.mdx` listed `os init`'s
templates as "`app` / `plugin` / `empty`" with nothing saying which of the two
artifacts the middle one makes — on the page a reader who does not yet know
there are two arrives at first. It now names the metadata package, says it is
not the kernel code plugin `os create plugin` writes, and links the chooser.

`content/docs/protocol/kernel/index.mdx` showed `os create plugin` under a bare
"Plugin Development" heading. The command it shows was already the right one for
what the section describes, so nothing there routed a reader wrong, but the word
was still doing double duty on a page that scaffolds. One sentence now names the
artifact and points at the chooser.

`content/docs/getting-started/examples.mdx` is not falsified and is untouched:
its only `os init` sentence is about the starter tree that command emits, names
no template and routes no one to a scaffolder choice, and its three other
"plugin" uses are the runtime auto-detection sense and the manifest `type`
literal — neither is the two-scaffolder collision.

No flag and no subcommand is renamed here either.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFY46JydE1gMxQG1TqBcMZ

Author: claude

content/docs/getting-started/your-first-project.mdx

@@ -70,7 +70,10 @@ so explicitly.
 
 <Callout type="tip">
 `os init` (from `@objectstack/cli`) is an alternative scaffolder with `app` /
-`plugin` / `empty` templates — see the [CLI reference](/docs/deployment/cli#os-init).
+`plugin` / `empty` templates. Its `plugin` template writes a **metadata package** —
+declarative objects another stack loads — and **not** the kernel code plugin
+`os create plugin` writes; [Which scaffolder?](/docs/deployment/cli#os-init) routes
+between all four entry points by the artifact you want rather than by the word.
 `npm create objectstack` is the recommended entry point for new standalone projects.
 </Callout>
 

content/docs/protocol/kernel/index.mdx

@@ -383,6 +383,12 @@ All system configuration lives in Git:
 ## Developer Experience
 
 ### Plugin Development
+
+`os create plugin` scaffolds a **kernel code plugin** — TypeScript implementing the
+`Plugin` contract this page describes. It is not the **metadata package** that
+`os init -t plugin` writes, which holds declarative objects and no kernel code;
+[Which scaffolder?](/docs/deployment/cli#os-init) routes between the two by artifact.
+
 ```bash
 # Scaffold new plugin (created as ./plugin-<name>/ in the current directory)
 os create plugin slack-integration