chore: Release v4.0.4 - Revert to local marketplace installation

Reverted from GitHub-hosted marketplace to local marketplace file installation method. This allows us to resolve issues with better-sqlite3 native module builds before enabling GitHub marketplace distribution.

Changes:
- Simplified .claude-plugin/marketplace.json (removed metadata, version fields)
- Updated README installation instructions to use local .claude-plugin/marketplace.json
- Bumped version to 4.0.4

Installation now requires cloning the repo and using:
/plugin marketplace add .claude-plugin/marketplace.json

Will restore GitHub marketplace method once native module issues are resolved.

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

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

.claude-plugin/marketplace.json

@@ -3,19 +3,11 @@
   "owner": {
     "name": "Alex Newman"
   },
-  "metadata": {
-    "description": "Alex Newman's Claude Code plugins",
-    "version": "1.0.0"
-  },
   "plugins": [
     {
       "name": "claude-mem",
       "source": "./plugin",
-      "description": "Persistent memory system for Claude Code - seamlessly preserve context across sessions",
-      "version": "4.0.3",
-      "author": {
-        "name": "Alex Newman"
-      }
+      "description": "Persistent memory system for Claude Code"
     }
   ]
 }

README.md

@@ -5,7 +5,7 @@
 Claude-Mem seamlessly preserves context across sessions by automatically capturing tool usage observations, generating semantic summaries, and making them available to future sessions. This enables Claude to maintain continuity of knowledge about projects even after sessions end or reconnect.
 
 [![License: AGPL-3.0](https://img.shields.io/badge/License-AGPL%203.0-blue.svg)](LICENSE)
-[![Version](https://img.shields.io/badge/version-4.0.0-green.svg)](package.json)
+[![Version](https://img.shields.io/badge/version-4.0.4-green.svg)](package.json)
 [![Node](https://img.shields.io/badge/node-%3E%3D18.0.0-brightgreen.svg)](package.json)
 
 ---
@@ -184,13 +184,17 @@ SQLite database (`${CLAUDE_PLUGIN_ROOT}/data/claude-mem.db`) with tables:
 node --version  # Should be >= 18.0.0
 ```
 
-### Method 1: Claude Code Marketplace (Recommended)
+### Method 1: Local Marketplace Installation (Recommended)
 
-Install directly from Claude Code using the plugin marketplace:
+Install using the local marketplace file:
 
 ```bash
-# Add the marketplace
-/plugin marketplace add thedotmack/claude-mem
+# Clone or download the repository
+git clone https://github.com/thedotmack/claude-mem.git
+cd claude-mem
+
+# Add the local marketplace to Claude Code
+/plugin marketplace add .claude-plugin/marketplace.json
 
 # Install the plugin
 /plugin install claude-mem

package.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-mem",
-  "version": "4.0.3",
+  "version": "4.0.4",
   "description": "Memory compression system for Claude Code - persist context across sessions",
   "keywords": [
     "claude",