feat: package as a Claude Code plugin with a deterministic quality gate

Workflows move to skills/<name>/SKILL.md so the repo installs as a plugin.
scripts/quality-gate runs only the checks of the requested tier on the diff
and reports missing tools as unverified instead of passing them. Hooks block
stopping on a failed or stale gate, guard destructive shell commands and
format edited files with the project's own formatter.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.claude-plugin/marketplace.json

@@ -0,0 +1,14 @@
+{
+  "name": "dev-workflows",
+  "owner": {
+    "name": "Evandro Fonseca Junior",
+    "url": "https://github.com/evandrodevbr"
+  },
+  "plugins": [
+    {
+      "name": "dev-workflows",
+      "source": "./",
+      "description": "Roteador por nível, agentes, gate de qualidade e workflows de front, back, arquitetura, segurança e README."
+    }
+  ]
+}