feat: add draggable Quick Settings sidebar handle

Add ability to reposition the Quick Settings sidebar handle by dragging it vertically on both desktop and mobile devices. The handle combines toggle and drag functionality in a single compact button.

Key features:
- Drag handle vertically to reposition on screen
- Click to toggle sidebar open/closed
- Smart gesture detection (5px threshold distinguishes drag from click)
- Visual feedback with blue grip icon during drag
- Position persists in localStorage across sessions
- Constrained to 10-90% of viewport height
- Full touch support with proper scroll prevention on mobile
- Responsive positioning (top-based on desktop, bottom-based on mobile)

src/components/QuickSettingsPanel.jsx

@@ -1,9 +1,9 @@
-import React, { useState, useEffect } from 'react';
-import { 
-  ChevronLeft, 
-  ChevronRight, 
-  Maximize2, 
-  Eye, 
+import React, { useState, useEffect, useRef, useCallback } from 'react';
+import {
+  ChevronLeft,
+  ChevronRight,
+  Maximize2,
+  Eye,
   Settings2,
   Moon,
   Sun,
@@ -12,7 +12,8 @@ import {
   Brain,
   Sparkles,
   FileText,
-  Languages
+  Languages,
+  GripVertical
 } from 'lucide-react';
 import DarkModeToggle from './DarkModeToggle';
 import { useTheme } from '../contexts/ThemeContext';
@@ -38,11 +39,153 @@ const QuickSettingsPanel = ({
   });
   const { isDarkMode } = useTheme();
 
+  // Draggable handle state
+  const [handlePosition, setHandlePosition] = useState(() => {
+    const saved = localStorage.getItem('quickSettingsHandlePosition');
+    if (saved) {
+      const parsed = JSON.parse(saved);
+      return parsed.y;
+    }
+    return 50; // Default to 50% (middle of screen)
+  });
+
+  const [isDragging, setIsDragging] = useState(false);
+  const [dragStartY, setDragStartY] = useState(0);
+  const [dragStartPosition, setDragStartPosition] = useState(0);
+  const [hasMoved, setHasMoved] = useState(false); // Track if user has moved during drag
+  const handleRef = useRef(null);
+  const constraintsRef = useRef({ min: 10, max: 90 }); // Percentage constraints
+  const dragThreshold = 5; // Pixels to move before it's considered a drag
+
   useEffect(() => {
     setLocalIsOpen(isOpen);
   }, [isOpen]);
 
-  const handleToggle = () => {
+  // Save handle position to localStorage when it changes
+  useEffect(() => {
+    localStorage.setItem('quickSettingsHandlePosition', JSON.stringify({ y: handlePosition }));
+  }, [handlePosition]);
+
+  // Calculate position from percentage
+  const getPositionStyle = useCallback(() => {
+    if (isMobile) {
+      // On mobile, convert percentage to pixels from bottom
+      const bottomPixels = (window.innerHeight * handlePosition) / 100;
+      return { bottom: `${bottomPixels}px` };
+    } else {
+      // On desktop, use top with percentage
+      return { top: `${handlePosition}%`, transform: 'translateY(-50%)' };
+    }
+  }, [handlePosition, isMobile]);
+
+  // Handle mouse/touch start
+  const handleDragStart = useCallback((e) => {
+    // Don't prevent default yet - we want to allow click if no drag happens
+    e.stopPropagation();
+
+    const clientY = e.type.includes('touch') ? e.touches[0].clientY : e.clientY;
+    setDragStartY(clientY);
+    setDragStartPosition(handlePosition);
+    setHasMoved(false);
+    setIsDragging(false); // Don't set dragging until threshold is passed
+  }, [handlePosition]);
+
+  // Handle mouse/touch move
+  const handleDragMove = useCallback((e) => {
+    if (dragStartY === 0) return; // Not in a potential drag
+
+    const clientY = e.type.includes('touch') ? e.touches[0].clientY : e.clientY;
+    const deltaY = Math.abs(clientY - dragStartY);
+
+    // Check if we've moved past threshold
+    if (!isDragging && deltaY > dragThreshold) {
+      setIsDragging(true);
+      setHasMoved(true);
+      document.body.style.cursor = 'grabbing';
+      document.body.style.userSelect = 'none';
+
+      // Prevent body scroll on mobile during drag
+      if (e.type.includes('touch')) {
+        document.body.style.overflow = 'hidden';
+        document.body.style.position = 'fixed';
+        document.body.style.width = '100%';
+      }
+    }
+
+    if (!isDragging) return;
+
+    // Prevent scrolling on touch move
+    if (e.type.includes('touch')) {
+      e.preventDefault();
+    }
+
+    const actualDeltaY = clientY - dragStartY;
+
+    // For top-based positioning (desktop), moving down increases top percentage
+    // For bottom-based positioning (mobile), we need to invert
+    let percentageDelta;
+    if (isMobile) {
+      // On mobile, moving down should decrease bottom position (increase percentage from top)
+      percentageDelta = -(actualDeltaY / window.innerHeight) * 100;
+    } else {
+      // On desktop, moving down should increase top position
+      percentageDelta = (actualDeltaY / window.innerHeight) * 100;
+    }
+
+    let newPosition = dragStartPosition + percentageDelta;
+
+    // Apply constraints
+    newPosition = Math.max(constraintsRef.current.min, Math.min(constraintsRef.current.max, newPosition));
+
+    setHandlePosition(newPosition);
+  }, [isDragging, dragStartY, dragStartPosition, isMobile, dragThreshold]);
+
+  // Handle mouse/touch end
+  const handleDragEnd = useCallback(() => {
+    setIsDragging(false);
+    setDragStartY(0);
+    document.body.style.cursor = '';
+    document.body.style.userSelect = '';
+
+    // Restore body scroll on mobile
+    document.body.style.overflow = '';
+    document.body.style.position = '';
+    document.body.style.width = '';
+  }, []);
+
+  // Set up global event listeners for drag
+  useEffect(() => {
+    if (dragStartY !== 0) {
+      // Mouse events
+      const handleMouseMove = (e) => handleDragMove(e);
+      const handleMouseUp = () => handleDragEnd();
+
+      // Touch events
+      const handleTouchMove = (e) => handleDragMove(e);
+      const handleTouchEnd = () => handleDragEnd();
+
+      document.addEventListener('mousemove', handleMouseMove);
+      document.addEventListener('mouseup', handleMouseUp);
+      document.addEventListener('touchmove', handleTouchMove, { passive: false });
+      document.addEventListener('touchend', handleTouchEnd);
+
+      return () => {
+        document.removeEventListener('mousemove', handleMouseMove);
+        document.removeEventListener('mouseup', handleMouseUp);
+        document.removeEventListener('touchmove', handleTouchMove);
+        document.removeEventListener('touchend', handleTouchEnd);
+      };
+    }
+  }, [dragStartY, handleDragMove, handleDragEnd]);
+
+  const handleToggle = (e) => {
+    // Don't toggle if user was dragging
+    if (hasMoved) {
+      e.preventDefault();
+      setHasMoved(false);
+      return;
+    }
+
     const newState = !localIsOpen;
     setLocalIsOpen(newState);
     onToggle(newState);
@@ -50,24 +193,37 @@ const QuickSettingsPanel = ({
 
   return (
     <>
-      {/* Pull Tab */}
-      <div
-        className={`fixed ${isMobile ? 'bottom-44' : 'top-1/2 -translate-y-1/2'} ${
+      {/* Pull Tab - Combined drag handle and toggle button */}
+      <button
+        ref={handleRef}
+        onClick={handleToggle}
+        onMouseDown={(e) => {
+          // Start drag on mousedown
+          handleDragStart(e);
+        }}
+        onTouchStart={(e) => {
+          // Start drag on touchstart
+          handleDragStart(e);
+        }}
+        className={`fixed ${
           localIsOpen ? 'right-64' : 'right-0'
-        } z-50 transition-all duration-150 ease-out`}
+        } z-50 ${isDragging ? '' : 'transition-all duration-150 ease-out'} bg-white dark:bg-gray-800 border ${
+          isDragging ? 'border-blue-500 dark:border-blue-400' : 'border-gray-200 dark:border-gray-700'
+        } rounded-l-md p-2 hover:bg-gray-100 dark:hover:bg-gray-700 transition-colors shadow-lg ${
+          isDragging ? 'cursor-grabbing' : 'cursor-pointer'
+        } touch-none`}
+        style={{ ...getPositionStyle(), touchAction: 'none', WebkitTouchCallout: 'none', WebkitUserSelect: 'none' }}
+        aria-label={isDragging ? 'Dragging handle' : localIsOpen ? 'Close settings panel' : 'Open settings panel'}
+        title={isDragging ? 'Dragging...' : 'Click to toggle, drag to move'}
       >
-        <button
-          onClick={handleToggle}
-          className="bg-white dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded-l-md p-2 hover:bg-gray-100 dark:hover:bg-gray-700 transition-colors shadow-lg"
-          aria-label={localIsOpen ? 'Close settings panel' : 'Open settings panel'}
-        >
-          {localIsOpen ? (
-            <ChevronRight className="h-5 w-5 text-gray-600 dark:text-gray-400" />
-          ) : (
-            <ChevronLeft className="h-5 w-5 text-gray-600 dark:text-gray-400" />
-          )}
-        </button>
-      </div>
+        {isDragging ? (
+          <GripVertical className="h-5 w-5 text-blue-500 dark:text-blue-400" />
+        ) : localIsOpen ? (
+          <ChevronRight className="h-5 w-5 text-gray-600 dark:text-gray-400" />
+        ) : (
+          <ChevronLeft className="h-5 w-5 text-gray-600 dark:text-gray-400" />
+        )}
+      </button>
 
       {/* Panel */}
       <div