fix(tools-tab): resolve remaining PR review comments

- api_v3: use getattr(api_v3, 'plugin_manager', None) instead of the
  module-level plugin_manager (always None); app.py sets the blueprint
  attribute, not the module global, so the fallback to plugin-repos was
  always taken
- pages_v3: replace broad except Exception in _load_tools_partial with
  specific TemplateNotFound / OSError handlers and add [Pages V3][Tools]
  context prefix to log messages and error responses for easier Pi
  debugging
- base.html: add Tools tab branch to the HTMX-unavailable fallback block
  in loadTabContent so the tab loads gracefully via direct fetch if HTMX
  never initialises

Skipped: auth on execute_system_action — pre-existing app-wide design;
reboot/shutdown and all other system actions share the same exposure.
An app-level auth layer is the correct fix and is out of scope here.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web_interface/blueprints/api_v3.py

@@ -1666,7 +1666,8 @@ def execute_system_action():
                 'output': _truncate_output(result.stdout, result.stderr)
             })
         elif action == 'install_plugin_requirements':
-            plugins_dir = Path(plugin_manager.plugins_dir) if plugin_manager else PROJECT_ROOT / 'plugin-repos'
+            active_pm = getattr(api_v3, 'plugin_manager', None)
+            plugins_dir = Path(active_pm.plugins_dir) if active_pm else PROJECT_ROOT / 'plugin-repos'
             results = []
             if plugins_dir.exists():
                 for p in sorted(plugins_dir.iterdir()):

web_interface/blueprints/pages_v3.py

@@ -1,4 +1,5 @@
 from flask import Blueprint, render_template, flash
+from jinja2 import TemplateNotFound
 from markupsafe import escape
 import json
 import logging
@@ -454,9 +455,12 @@ def _load_tools_partial():
     """Load tools/utilities partial."""
     try:
         return render_template('v3/partials/tools.html')
-    except Exception:
-        logger.error("Error loading partial", exc_info=True)
-        return "Error loading partial", 500
+    except TemplateNotFound:
+        logger.error("[Pages V3][Tools] Template not found: v3/partials/tools.html", exc_info=True)
+        return "[Pages V3][Tools] Template is missing.", 500
+    except OSError as exc:
+        logger.error("[Pages V3][Tools] I/O error loading tools partial: %s", exc, exc_info=True)
+        return "[Pages V3][Tools] Failed to load due to a file system error. Check logs.", 500
 
 
 def _load_plugin_config_partial(plugin_id):

web_interface/templates/v3/base.html

@@ -1922,7 +1922,22 @@
                             if (tab === 'overview' && typeof loadOverviewDirect === 'function') loadOverviewDirect();
                             else if (tab === 'wifi' && typeof loadWifiDirect === 'function') loadWifiDirect();
                             else if (tab === 'plugins' && typeof loadPluginsDirect === 'function') loadPluginsDirect();
-                        }
+                            else if (tab === 'tools') {
+                                fetch('/v3/partials/tools')
+                                    .then(r => {
+                                        if (!r.ok) throw new Error(r.status + ' ' + r.statusText);
+                                        return r.text();
+                                    })
+                                    .then(html => {
+                                        contentEl.innerHTML = html;
+                                        contentEl.setAttribute('data-loaded', 'true');
+                                        if (window.Alpine) window.Alpine.initTree(contentEl);
+                                    })
+                                    .catch(err => {
+                                        console.error('Failed to load tools content:', err);
+                                        contentEl.innerHTML = '<div class="bg-red-50 border border-red-200 rounded-lg p-4"><p class="text-red-800">Failed to load Tools. Please refresh the page.</p></div>';
+                                    });
+                            }
                     }, 100);
                 },