fix: correct plugin import path in docs, wire up orphaned footer template

docs/PLUGIN_DEVELOPMENT.md referenced a nonexistent hbd/plugin.py and
hbd/plugins/ directory; the real module is hbd/client/plugin.py with
plugins under hbd/client/plugins/, as README.md and the actual code
already use. Anyone following the doc would hit ModuleNotFoundError.

foot.html was never included by any template (confirmed via git grep
and template audit) despite being actively maintained; wired it into
about.html. menu.html was fully commented out and unreferenced, so
removed it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/PLUGIN_DEVELOPMENT.md

@@ -21,7 +21,7 @@ Heartbeat's plugin system is designed to be simple yet powerful. Plugins are Pyt
 ### Key Concepts
 
 - **Plugin Registry**: Central registry that manages all loaded plugins
-- **Plugin Loader**: Automatically discovers and loads plugins from the `hbd/plugins/` directory
+- **Plugin Loader**: Automatically discovers and loads plugins from the `hbd/client/plugins/` directory
 - **Plugin Types**: InfoPlugin (static data) and MonitorPlugin (periodic metrics)
 - **Async/Await**: All plugin methods are async for non-blocking operation
 
@@ -64,7 +64,7 @@ Decide whether your plugin collects static information (InfoPlugin) or dynamic m
 
 ### Step 2: Create Plugin File
 
-Create a new Python file in `hbd/plugins/` directory:
+Create a new Python file in `hbd/client/plugins/` directory:
 
 ```python
 """
@@ -82,7 +82,7 @@ try:
 except ImportError:
     psutil = None
 
-from hbd.plugin import MonitorPlugin  # or InfoPlugin
+from hbd.client.plugin import MonitorPlugin  # or InfoPlugin
 
 logger = logging.getLogger(__name__)
 
@@ -193,7 +193,7 @@ from pathlib import Path
 # Add parent directory to path
 sys.path.insert(0, str(Path(__file__).parent))
 
-from hbd.plugins.my_awesome_plugin import MyAwesomePlugin
+from hbd.client.plugins.my_awesome_plugin import MyAwesomePlugin
 
 async def test():
     # Create plugin instance
@@ -224,7 +224,7 @@ Understanding the plugin lifecycle helps you implement plugins correctly:
 
 ```
 1. Plugin Discovery
-   └─> Loader scans hbd/plugins/ directory
+   └─> Loader scans hbd/client/plugins/ directory
    └─> Finds Python files (except those starting with _)
    └─> Imports modules
 
@@ -378,7 +378,7 @@ Document your plugin thoroughly:
 ### Example 1: Simple InfoPlugin
 
 ```python
-from hbd.plugin import InfoPlugin
+from hbd.client.plugin import InfoPlugin
 import platform
 
 class SimpleInfoPlugin(InfoPlugin):
@@ -406,7 +406,7 @@ plugin = SimpleInfoPlugin
 ### Example 2: MonitorPlugin with State
 
 ```python
-from hbd.plugin import MonitorPlugin
+from hbd.client.plugin import MonitorPlugin
 import time
 
 class CounterPlugin(MonitorPlugin):
@@ -442,7 +442,7 @@ plugin = CounterPlugin
 ### Example 3: Plugin with External Command
 
 ```python
-from hbd.plugin import MonitorPlugin
+from hbd.client.plugin import MonitorPlugin
 import asyncio
 
 class CommandPlugin(MonitorPlugin):
@@ -561,7 +561,7 @@ python -m hbd.hbc -c test_config.yaml --verbose
 
 ## Further Reading
 
-- [Plugin Framework Source](../hbd/plugin.py) - Core plugin implementation
+- [Plugin Framework Source](../hbd/client/plugin.py) - Core plugin implementation
-- [Built-in Plugins](../hbd/plugins/) - Examples of working plugins
+- [Built-in Plugins](../hbd/client/plugins/) - Examples of working plugins
 - [Nagios Integration](NAGIOS_INTEGRATION.md) - Running external plugins
 - [Configuration Guide](../hbd/config_example.yaml) - Full configuration reference

hbd/server/templates/about.html

@@ -107,6 +107,8 @@
       </section>
     </div>
 
+    {% include 'foot.html' %}
+
     <script>
       (function() {
         var startEpoch = {{ start_epoch }};

hbd/server/templates/menu.html

@@ -1,2 +0,0 @@
-<!-- <label for="drawer-toggle" id="drawer-toggle-label"></label>
-s<header>{{ header }}</header> -->