feat: create HighlightsTab component with color picker

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

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

__tests__/components/highlights-tab.test.tsx

@@ -0,0 +1,58 @@
+import { render, screen, fireEvent } from '@testing-library/react'
+import { HighlightsTab } from '@/components/bible/highlights-tab'
+import { BibleVerse } from '@/types'
+
+describe('HighlightsTab', () => {
+  const mockVerse: BibleVerse = {
+    id: 'v-1',
+    verseNum: 1,
+    text: 'In the beginning God created the heavens and the earth'
+  }
+
+  it('should render highlight button when verse not highlighted', () => {
+    render(
+      <HighlightsTab
+        verse={mockVerse}
+        isHighlighted={false}
+        currentColor={null}
+        onToggleHighlight={() => {}}
+        onColorChange={() => {}}
+      />
+    )
+
+    expect(screen.getByText(/Highlight/i)).toBeInTheDocument()
+  })
+
+  it('should render color picker when verse is highlighted', () => {
+    render(
+      <HighlightsTab
+        verse={mockVerse}
+        isHighlighted={true}
+        currentColor="yellow"
+        onToggleHighlight={() => {}}
+        onColorChange={() => {}}
+      />
+    )
+
+    expect(screen.getByText(/Remove highlight/i)).toBeInTheDocument()
+  })
+
+  it('should call onColorChange when color is selected', () => {
+    const onColorChange = jest.fn()
+
+    render(
+      <HighlightsTab
+        verse={mockVerse}
+        isHighlighted={true}
+        currentColor="yellow"
+        onToggleHighlight={() => {}}
+        onColorChange={onColorChange}
+      />
+    )
+
+    const blueButton = screen.getByTestId('color-blue')
+    fireEvent.click(blueButton)
+
+    expect(onColorChange).toHaveBeenCalledWith('blue')
+  })
+})

components/bible/highlights-tab.tsx

@@ -0,0 +1,90 @@
+'use client'
+import { Box, Button, Grid, Typography, Divider } from '@mui/material'
+import { BibleVerse, HighlightColor } from '@/types'
+
+const HIGHLIGHT_COLORS: HighlightColor[] = ['yellow', 'orange', 'pink', 'blue']
+
+const COLOR_MAP: Record<HighlightColor, { bg: string; hex: string }> = {
+  yellow: { bg: 'rgba(255, 193, 7, 0.3)', hex: '#FFC107' },
+  orange: { bg: 'rgba(255, 152, 0, 0.3)', hex: '#FF9800' },
+  pink: { bg: 'rgba(233, 30, 99, 0.3)', hex: '#E91E63' },
+  blue: { bg: 'rgba(33, 150, 243, 0.3)', hex: '#2196F3' }
+}
+
+interface HighlightsTabProps {
+  verse: BibleVerse | null
+  isHighlighted: boolean
+  currentColor: HighlightColor | null
+  onToggleHighlight: () => void
+  onColorChange: (color: HighlightColor) => void
+}
+
+export function HighlightsTab({
+  verse,
+  isHighlighted,
+  currentColor,
+  onToggleHighlight,
+  onColorChange
+}: HighlightsTabProps) {
+  if (!verse) return null
+
+  return (
+    <Box sx={{ p: 2 }}>
+      {!isHighlighted ? (
+        <Button
+          fullWidth
+          variant="contained"
+          color="primary"
+          onClick={onToggleHighlight}
+        >
+          Highlight this verse
+        </Button>
+      ) : (
+        <>
+          <Button
+            fullWidth
+            variant="outlined"
+            color="error"
+            onClick={onToggleHighlight}
+            sx={{ mb: 2 }}
+          >
+            Remove highlight
+          </Button>
+
+          <Typography variant="subtitle2" sx={{ mb: 1 }}>
+            Highlight Color
+          </Typography>
+
+          <Grid container spacing={1} sx={{ mb: 2 }}>
+            {HIGHLIGHT_COLORS.map((color) => (
+              <Grid item xs={3} key={color}>
+                <Button
+                  data-testid={`color-${color}`}
+                  fullWidth
+                  variant={currentColor === color ? 'contained' : 'outlined'}
+                  onClick={() => onColorChange(color)}
+                  sx={{
+                    bgcolor: COLOR_MAP[color].bg,
+                    borderColor: COLOR_MAP[color].hex,
+                    border: currentColor === color ? `2px solid ${COLOR_MAP[color].hex}` : undefined,
+                    minHeight: 50,
+                    textTransform: 'capitalize',
+                    color: currentColor === color ? '#000' : 'inherit'
+                  }}
+                >
+                  {color}
+                </Button>
+              </Grid>
+            ))}
+          </Grid>
+
+          <Divider sx={{ my: 2 }} />
+
+          <Typography variant="body2" color="textSecondary">
+            You can highlight the same verse multiple times with different colors.
+          </Typography>
+        </>
+      )}
+    </Box>
+  )
+}

components/bible/verse-details-panel.tsx

@@ -3,6 +3,7 @@ import { useState, useEffect } from 'react'
 import { Box, Paper, Typography, Tabs, Tab, IconButton, useMediaQuery, useTheme, TextField, Button } from '@mui/material'
 import { Close, Bookmark, BookmarkBorder } from '@mui/icons-material'
 import { BibleVerse } from '@/types'
+import { HighlightsTab } from './highlights-tab'
 
 interface VersDetailsPanelProps {
   verse: BibleVerse | null
@@ -118,9 +119,13 @@ export function VersDetailsPanel({
         )}
 
         {tabValue === 1 && (
-          <Typography variant="body2" color="text.secondary">
+          <HighlightsTab
-            Highlight colors coming soon
+            verse={verse}
-          </Typography>
+            isHighlighted={false} // TODO: get from state
+            currentColor={null} // TODO: get from state
+            onToggleHighlight={() => {}} // TODO: implement
+            onColorChange={() => {}} // TODO: implement
+          />
         )}
 
         {tabValue === 2 && (