feat(help): Add floating help button to all pages

Replaced inline HelpButton components with a global FloatingHelpButton
that appears fixed in the top-right corner of all pages. The button:
- Automatically detects the current route and links to the appropriate help page
- Uses a consistent position across all pages (fixed, top-right)
- Is hidden on help pages themselves
- Works on both business and platform layouts

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

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

frontend/src/pages/Tasks.tsx

@@ -2,7 +2,6 @@ import React, { useState, useMemo } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import axios from '../api/client';
-import HelpButton from '../components/HelpButton';
 import {
   Plus,
   Play,
@@ -259,16 +258,13 @@ const Tasks: React.FC = () => {
     <div className="p-6 max-w-7xl mx-auto">
       {/* Header */}
       <div className="flex items-center justify-between mb-6">
-        <div className="flex items-start gap-4">
-          <div>
-            <h1 className="text-3xl font-bold text-gray-900 dark:text-white">
-              {t('Tasks')}
-            </h1>
-            <p className="text-gray-600 dark:text-gray-400 mt-1">
-              Schedule and manage automated plugin executions
-            </p>
-          </div>
-          <HelpButton helpPath="/help/tasks" />
+        <div>
+          <h1 className="text-3xl font-bold text-gray-900 dark:text-white">
+            {t('Tasks')}
+          </h1>
+          <p className="text-gray-600 dark:text-gray-400 mt-1">
+            Schedule and manage automated plugin executions
+          </p>
         </div>
         <button
           onClick={() => setShowCreateModal(true)}