Package BCQuality as an installable plugin (experiment) (#84)

* Package BCQuality as an installable plugin (experiment)

Adds a marketplace + plugin manifest and a bridge review skill that drives the existing Entry protocol from a plugin host. No changes to knowledge or routing logic.

* Bridge skill: make enabled-layers configurable; note layer-pruning limit and manifest choice

Addresses PR #84 review (JesperSchulz): #2 layer policy has no hook in the plugin path -> expose BCQUALITY_ENABLED_LAYERS and document that it narrows discovery only, not a hard deny; #3 document the .claude-plugin manifest choice (verified on Copilot CLI).

---------

Co-authored-by: wenjiefan <wenjiefan@microsoft.com>

.claude-plugin/marketplace.json

@@ -0,0 +1,15 @@
+{
+  "name": "bcquality",
+  "owner": {
+    "name": "microsoft/BCQuality",
+    "url": "https://github.com/microsoft/BCQuality"
+  },
+  "plugins": [
+    {
+      "name": "bcquality",
+      "source": "./",
+      "description": "Business Central AL quality knowledge base and review skills, packaged as an installable plugin. Ships the entire BCQuality tree (skills, knowledge, tools) so the Entry routing protocol runs against the installed clone.",
+      "version": "0.1.0"
+    }
+  ]
+}

.claude-plugin/plugin.json

@@ -0,0 +1,9 @@
+{
+  "name": "bcquality",
+  "description": "Quality skills and knowledge for Business Central development. Exposes a review bridge skill that drives the BCQuality Entry protocol over the installed knowledge base.",
+  "version": "0.1.0",
+  "author": {
+    "name": "microsoft/BCQuality",
+    "url": "https://github.com/microsoft/BCQuality"
+  }
+}