fix: Add marketplace.json and correct install instructions

- Add marketplace.json so repo can act as a plugin marketplace
- Fix README: two-step install (add marketplace, then install plugin)
- Fix AGENTS.md with same corrected instructions

Users must now:
  /plugin marketplace add 0xDarkMatter/claude-mods
  /plugin install claude-mods@0xDarkMatter-claude-mods

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

AGENTS.md

@@ -11,8 +11,11 @@ This is **claude-mods** - a collection of custom extensions for Claude Code:
 ## Installation
 
 ```bash
-# Plugin install (recommended)
-/plugin install 0xDarkMatter/claude-mods
+# Step 1: Add the marketplace
+/plugin marketplace add 0xDarkMatter/claude-mods
+
+# Step 2: Install the plugin (globally)
+/plugin install claude-mods@0xDarkMatter-claude-mods
 
 # Or clone and run install script
 git clone https://github.com/0xDarkMatter/claude-mods.git

README.md

@@ -51,11 +51,14 @@ claude-mods/
 ### Plugin Install (Recommended)
 
 ```bash
-# In Claude Code, run:
-/plugin install 0xDarkMatter/claude-mods
+# Step 1: Add the marketplace
+/plugin marketplace add 0xDarkMatter/claude-mods
+
+# Step 2: Install the plugin
+/plugin install claude-mods@0xDarkMatter-claude-mods
 ```
 
-This installs directly from GitHub. Toggle on/off with `/plugin` menu.
+This installs globally (available in all projects). Toggle on/off with `/plugin` menu.
 
 ### Script Install
 

marketplace.json

@@ -0,0 +1,14 @@
+{
+  "name": "claude-mods",
+  "description": "Custom commands, skills, agents, and rules for Claude Code",
+  "plugins": [
+    {
+      "name": "claude-mods",
+      "description": "23 expert agents, 11 commands, 30 skills, 4 rules, and output styles for Claude Code",
+      "source": {
+        "type": "git",
+        "url": "https://github.com/0xDarkMatter/claude-mods.git"
+      }
+    }
+  ]
+}