feat: add MemPalace Claude Code plugin with hooks and instructions

- Introduced README.md for plugin overview and installation instructions.
- Added hooks configuration in hooks.json for auto-save and pre-compact functionality.
- Implemented stop and pre-compact hooks in bash scripts for memory management.
- Created marketplace.json and plugin.json for plugin metadata and versioning.
- Developed skills and instructions for help, init, mine, search, and status functionalities.
- Added CLI commands for executing hooks and displaying skill instructions.
- Implemented hooks_cli.py for handling hook logic and JSON input/output.
- Enhanced instruction files for user guidance on setup and usage.
- Updated .gitignore to exclude additional files.
- Created GitHub Actions workflow for syncing plugin version on push.

.claude-plugin/marketplace.json

@@ -0,0 +1,18 @@
+{
+  "name": "mempalace",
+  "owner": {
+    "name": "milla-jovovich",
+    "url": "https://github.com/milla-jovovich"
+  },
+  "plugins": [
+    {
+      "name": "mempalace",
+      "source": ".",
+      "description": "AI memory system — mine projects and conversations into a searchable palace. 19 MCP tools, auto-save hooks, guided setup.",
+      "version": "3.0.0",
+      "author": {
+        "name": "milla-jovovich"
+      }
+    }
+  ]
+}