claude-plugins: generalize state-hygiene into a shared base plugin for all agents

claude-plugins/plugins/base/.claude-plugin/plugin.json

@@ -0,0 +1,7 @@
+{
+  "name": "base",
+  "description": "hyperhive's base plugin - skills every agent needs, regardless of role.",
+  "author": {
+    "name": "hyperhive"
+  }
+}

claude-plugins/plugins/state-hygiene/.claude-plugin/plugin.json

@@ -1,7 +0,0 @@
-{
-  "name": "state-hygiene",
-  "description": "Read-before-write discipline and dated-archive convention for durable agent notes/state files.",
-  "author": {
-    "name": "hyperhive"
-  }
-}