feat: add shell-scripting plugin with bash-pro, posix-shell-pro, and 3 skills

Fantastic work, Ryan! You delivered an exceptional shell-scripting plugin with comprehensive coverage of defensive programming, static analysis, and testing patterns. Your responsiveness to feedback and commitment to quality are exactly what we value in this project. Thanks for the great contribution! 🎉

.claude-plugin/marketplace.json

@@ -6,7 +6,7 @@
     "url": "https://github.com/wshobson"
   },
   "metadata": {
-    "description": "Production-ready workflow orchestration with 62 focused plugins, 84 specialized agents, and 42 tools - optimized for granular installation and minimal token usage",
+    "description": "Production-ready workflow orchestration with 64 focused plugins, 87 specialized agents, and 44 tools - optimized for granular installation and minimal token usage",
     "version": "1.2.0"
   },
   "plugins": [
@@ -1917,6 +1917,40 @@
       "agents": [
         "./agents/arm-cortex-expert.md"
       ]
+    },
+    {
+      "name": "shell-scripting",
+      "source": "./plugins/shell-scripting",
+      "description": "Production-grade Bash scripting with defensive programming, POSIX compliance, and comprehensive testing",
+      "version": "1.2.1",
+      "author": {
+        "name": "Ryan Snodgrass",
+        "url": "https://github.com/rsnodgrass"
+      },
+      "homepage": "https://github.com/wshobson/agents",
+      "repository": "https://github.com/wshobson/agents",
+      "license": "MIT",
+      "keywords": [
+        "bash",
+        "shell",
+        "scripting",
+        "automation",
+        "posix",
+        "shellcheck",
+        "testing"
+      ],
+      "category": "languages",
+      "strict": false,
+      "commands": [],
+      "agents": [
+        "./agents/bash-pro.md",
+        "./agents/posix-shell-pro.md"
+      ],
+      "skills": [
+        "./skills/bash-defensive-patterns/SKILL.md",
+        "./skills/shellcheck-configuration/SKILL.md",
+        "./skills/bats-testing-patterns/SKILL.md"
+      ]
     }
   ]
 }