## Why

The current lifecycle proof uses the generic development plugin, but operators need a concrete SCUM server plugin that can be discovered from the plugin marketplace and used to create multiple SCUM server instances through the platform-mediated lifecycle path.

## What Changes

- Add a first-party local SCUM server plugin directory under `plugins/examples/scum-server-plugin`.
- Copy the existing safe plugin lifecycle pattern into SCUM-specific manifest metadata, create-form schema, plugin pages, and lifecycle action templates.
- Update plugin validation so both the development plugin and SCUM plugin are validated by default.
- Extend local debug smoke coverage so the plugin marketplace can discover the SCUM plugin and the platform can create multiple SCUM server instances from it.

## Capabilities

### New Capabilities

- `scum-server-plugin`: Provides a local SCUM game management plugin discoverable through the plugin marketplace and usable for multi-instance platform-mediated lifecycle workflows.

## Impact

- Affects `plugins/` example plugin assets, manifest validation, and tests.
- Affects `scripts/local-debug-smoke.sh` registration and API proof data.
- Does not add billing, cloud host sales, unrelated SaaS marketplace behavior, direct plugin-run transport, raw credentials, direct sockets, or raw host paths.