Initial implementation of pluginctl CLI tool

- Add comprehensive info command with plugin manifest parsing -
Implement global --plugin-path flag and PLUGINCTL_PLUGIN_PATH env var -
Add full test suite with fixtures for various plugin configurations -
Set up build system with Makefile, goreleaser, and golangci-lint -
Include development tools with pinned versions for reproducible builds

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

testdata/complete_plugin.json

@@ -0,0 +1,37 @@
+{
+    "id": "com.example.complete",
+    "name": "Complete Test Plugin",
+    "description": "A complete plugin with all features for testing",
+    "version": "2.1.0",
+    "min_server_version": "7.0.0",
+    "server": {
+        "executables": {
+            "linux-amd64": "server/dist/plugin-linux-amd64",
+            "darwin-amd64": "server/dist/plugin-darwin-amd64", 
+            "windows-amd64": "server/dist/plugin-windows-amd64.exe"
+        }
+    },
+    "webapp": {
+        "bundle_path": "webapp/dist/main.js"
+    },
+    "settings_schema": {
+        "header": "Complete Plugin Settings",
+        "footer": "Configure all settings for the complete plugin",
+        "settings": [
+            {
+                "key": "enable_feature",
+                "display_name": "Enable Main Feature",
+                "type": "bool",
+                "help_text": "Enable or disable the main plugin feature",
+                "default": true
+            },
+            {
+                "key": "api_endpoint",
+                "display_name": "API Endpoint",
+                "type": "text",
+                "help_text": "The API endpoint URL",
+                "default": "https://api.example.com"
+            }
+        ]
+    }
+}

testdata/invalid_plugin.json

@@ -0,0 +1,6 @@
+{
+    "id": "com.example.invalid",
+    "name": "Invalid Plugin",
+    "version": "1.0.0",
+    invalid_json_syntax: true
+}

testdata/minimal_plugin.json

@@ -0,0 +1,5 @@
+{
+    "id": "com.example.minimal",
+    "name": "Minimal Test Plugin",
+    "version": "1.0.0"
+}

testdata/plugin.json

@@ -0,0 +1,22 @@
+{
+  "id": "com.example.testplugin",
+  "name": "Test Plugin",
+  "description": "A test plugin for demonstrating pluginctl functionality",
+  "version": "1.0.0",
+  "min_server_version": "7.0.0",
+  "server": {
+    "executables": {
+      "linux-amd64": "server/dist/plugin-linux-amd64",
+      "darwin-amd64": "server/dist/plugin-darwin-amd64",
+      "windows-amd64": "server/dist/plugin-windows-amd64.exe"
+    }
+  },
+  "webapp": {
+    "bundle_path": "webapp/dist/main.js"
+  },
+  "settings_schema": {
+    "header": "Configure the Test Plugin",
+    "footer": "",
+    "settings": []
+  }
+}

testdata/server_only_plugin.json

@@ -0,0 +1,13 @@
+{
+    "id": "com.example.serveronly",
+    "name": "Server Only Plugin",
+    "description": "A plugin with only server-side code",
+    "version": "1.5.0",
+    "min_server_version": "8.0.0",
+    "server": {
+        "executables": {
+            "linux-amd64": "server/dist/plugin-linux-amd64",
+            "darwin-amd64": "server/dist/plugin-darwin-amd64"
+        }
+    }
+}

testdata/webapp_only_plugin.json

@@ -0,0 +1,9 @@
+{
+    "id": "com.example.webapponly", 
+    "name": "Webapp Only Plugin",
+    "description": "A plugin with only client-side code",
+    "version": "0.9.0",
+    "webapp": {
+        "bundle_path": "webapp/dist/bundle.js"
+    }
+}