feat(secubox-core): add plugins/catalog directory structure

Adds the missing /usr/share/secubox/plugins/catalog/ directory that is
documented but was not created by the package installer.

Changes:
- Create plugins/catalog directory structure
- Update Makefile to install catalog directory
- Add README explaining module catalog format
- Add example module catalog JSON file as reference

Directory structure:
- /usr/share/secubox/modules/ - Runtime module metadata (empty by design)
- /usr/share/secubox/plugins/catalog/ - Module catalog manifests
- /usr/share/secubox/scripts/ - Shared helper scripts

This completes the directory structure documented in the README.

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

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

package/secubox/secubox-core/Makefile

@@ -67,9 +67,13 @@ define Package/secubox-core/install
 	$(INSTALL_BIN) ./root/usr/libexec/rpcd/luci.secubox $(1)/usr/libexec/rpcd/
 
 	$(INSTALL_DIR) $(1)/usr/share/secubox/modules
+	$(INSTALL_DIR) $(1)/usr/share/secubox/plugins/catalog
 	$(INSTALL_DIR) $(1)/usr/share/secubox/scripts
 	$(INSTALL_DATA) ./root/usr/share/secubox/scripts/* $(1)/usr/share/secubox/scripts/
 
+	# Install module catalog files if they exist
+	-$(INSTALL_DATA) ./root/usr/share/secubox/plugins/catalog/*.json $(1)/usr/share/secubox/plugins/catalog/ 2>/dev/null || true
+
 	$(INSTALL_DIR) $(1)/var/run/secubox
 	$(INSTALL_DIR) $(1)/var/log/secubox
 endef

package/secubox/secubox-core/root/usr/share/secubox/plugins/catalog/README.md

@@ -0,0 +1,57 @@
+# SecuBox Module Catalog
+
+This directory contains module catalog entries for the SecuBox AppStore.
+
+## Structure
+
+Each module has its own JSON file:
+- `<module-id>.json` - Module manifest and metadata
+
+## Module Catalog Format
+
+```json
+{
+  "id": "module-name",
+  "name": "Display Name",
+  "version": "1.0.0",
+  "category": "networking",
+  "runtime": "native",
+  "packages": {
+    "required": ["package-name"],
+    "recommended": ["optional-package"]
+  },
+  "capabilities": ["capability-1", "capability-2"],
+  "requirements": {
+    "min_ram_mb": 64,
+    "min_storage_mb": 10
+  }
+}
+```
+
+## Categories
+
+- `networking` - Network services and utilities
+- `security` - Security and threat detection
+- `monitoring` - System and network monitoring
+- `iot` - IoT and home automation
+- `media` - Media streaming and entertainment
+- `system` - System utilities and management
+
+## Adding New Modules
+
+1. Create a new JSON file: `<module-id>.json`
+2. Define the manifest with required fields:
+   - `id`, `name`, `version`
+   - `category`, `runtime`
+   - `packages`, `capabilities`
+
+3. Test installation:
+   ```bash
+   secubox app install <module-id>
+   ```
+
+## Notes
+
+- Module catalog files are used by `secubox-appstore` for module discovery
+- The `luci-app-secubox/appstore/apps.json` file contains the master catalog
+- Individual module files here provide detailed metadata for advanced features

package/secubox/secubox-core/root/usr/share/secubox/plugins/catalog/example-module.json.sample

@@ -0,0 +1,41 @@
+{
+  "id": "example-module",
+  "name": "Example Module",
+  "version": "1.0.0",
+  "category": "system",
+  "runtime": "native",
+  "description": "Example module catalog entry demonstrating the structure",
+  "author": "SecuBox Team",
+  "license": "GPL-2.0",
+  "url": "https://github.com/your-org/example-module",
+  "icon": "⚙️",
+  "tags": ["example", "demo"],
+  "packages": {
+    "required": [
+      "luci-app-example-module"
+    ],
+    "recommended": [
+      "example-module-extras"
+    ]
+  },
+  "capabilities": [
+    "system-management",
+    "monitoring"
+  ],
+  "requirements": {
+    "min_ram_mb": 64,
+    "min_storage_mb": 10,
+    "openwrt_version": "24.10"
+  },
+  "hooks": {
+    "pre_install": "/usr/share/example-module/hooks/pre-install.sh",
+    "post_install": "/usr/share/example-module/hooks/post-install.sh",
+    "pre_remove": "/usr/share/example-module/hooks/pre-remove.sh",
+    "post_remove": "/usr/share/example-module/hooks/post-remove.sh"
+  },
+  "config": {
+    "uci_package": "example-module",
+    "init_script": "/etc/init.d/example-module",
+    "default_enabled": true
+  }
+}