fix: enforce plugin config schemas (#1272) (thanks @thewilloftheshadow)

Co-authored-by: thewilloftheshadow <thewilloftheshadow@users.noreply.github.com>

docs/cli/plugins.md

@@ -11,6 +11,7 @@ Manage Gateway plugins/extensions (loaded in-process).
 
 Related:
 - Plugin system: [Plugins](/plugin)
+- Plugin manifest + schema: [Plugin manifest](/plugins/manifest)
 - Security hardening: [Security](/gateway/security)
 
 ## Commands
@@ -28,6 +29,10 @@ clawdbot plugins update --all
 Bundled plugins ship with Clawdbot but start disabled. Use `plugins enable` to
 activate them.
 
+All plugins must ship a `clawdbot.plugin.json` file with an inline JSON Schema
+(`configSchema`, even if empty). Missing/invalid manifests or schemas prevent
+the plugin from loading and fail config validation.
+
 ### Install
 
 ```bash