feat(timer): add subtle pomodoro timer to header

- Added PomodoroTimer component with work/break modes
- Timer appears as icon in header, expands to full widget on click
- Supports 25m work, 5m short break, 15m long break cycles
- Shows progress bar, cycle dots, and mode switcher
- Plays sound when timer completes
- Can be minimized while running (shows pulsing indicator)

synculous-client/src/app/dashboard/layout.tsx

@@ -1,10 +1,11 @@
 'use client';
 
-import { useEffect, useRef } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import { useRouter, usePathname } from 'next/navigation';
 import { useAuth } from '@/components/auth/AuthProvider';
 import { useTheme } from '@/components/theme/ThemeProvider';
 import api from '@/lib/api';
+import PomodoroTimer from '@/components/timer/PomodoroTimer';
 import {
   HomeIcon,
   ListIcon,
@@ -38,6 +39,7 @@ export default function DashboardLayout({
   const { isDark, toggleDark } = useTheme();
   const router = useRouter();
   const pathname = usePathname();
+  const [isTimerOpen, setIsTimerOpen] = useState(false);
 
   const tzSynced = useRef(false);
 
@@ -89,6 +91,12 @@ export default function DashboardLayout({
             <span className="font-bold text-gray-900 dark:text-gray-100">Synculous</span>
           </div>
           <div className="flex items-center gap-2">
+            <div className="relative">
+              <PomodoroTimer 
+                isExpanded={isTimerOpen} 
+                onToggle={() => setIsTimerOpen(!isTimerOpen)} 
+              />
+            </div>
             <button
               onClick={toggleDark}
               className="p-2 text-gray-500 hover:text-gray-700 dark:text-gray-400 dark:hover:text-gray-200"

synculous-client/src/components/timer/PomodoroTimer.tsx

@@ -0,0 +1,255 @@
+'use client';
+
+import { useState, useEffect, useCallback, useRef } from 'react';
+import { TimerIcon, PlayIcon, PauseIcon, RotateCcwIcon, XIcon } from '@/components/ui/Icons';
+import { playTimerEnd } from '@/lib/sounds';
+
+interface PomodoroTimerProps {
+  isExpanded: boolean;
+  onToggle: () => void;
+}
+
+const WORK_MINUTES = 25;
+const SHORT_BREAK_MINUTES = 5;
+const LONG_BREAK_MINUTES = 15;
+
+export default function PomodoroTimer({ isExpanded, onToggle }: PomodoroTimerProps) {
+  const [mode, setMode] = useState<'work' | 'shortBreak' | 'longBreak'>('work');
+  const [timeLeft, setTimeLeft] = useState(WORK_MINUTES * 60);
+  const [isRunning, setIsRunning] = useState(false);
+  const [cycles, setCycles] = useState(0);
+  const intervalRef = useRef<NodeJS.Timeout | null>(null);
+
+  const getDuration = useCallback(() => {
+    switch (mode) {
+      case 'work': return WORK_MINUTES * 60;
+      case 'shortBreak': return SHORT_BREAK_MINUTES * 60;
+      case 'longBreak': return LONG_BREAK_MINUTES * 60;
+    }
+  }, [mode]);
+
+  const formatTime = (seconds: number) => {
+    const mins = Math.floor(seconds / 60);
+    const secs = seconds % 60;
+    return `${mins.toString().padStart(2, '0')}:${secs.toString().padStart(2, '0')}`;
+  };
+
+  const getProgress = () => {
+    const duration = getDuration();
+    return ((duration - timeLeft) / duration) * 100;
+  };
+
+  useEffect(() => {
+    if (isRunning && timeLeft > 0) {
+      intervalRef.current = setInterval(() => {
+        setTimeLeft(prev => {
+          if (prev <= 1) {
+            // Timer finished
+            playTimerEnd();
+            setIsRunning(false);
+            
+            if (mode === 'work') {
+              const newCycles = cycles + 1;
+              setCycles(newCycles);
+              // After 4 work sessions, take a long break
+              if (newCycles % 4 === 0) {
+                setMode('longBreak');
+                return LONG_BREAK_MINUTES * 60;
+              } else {
+                setMode('shortBreak');
+                return SHORT_BREAK_MINUTES * 60;
+              }
+            } else {
+              // Break is over, back to work
+              setMode('work');
+              return WORK_MINUTES * 60;
+            }
+          }
+          return prev - 1;
+        });
+      }, 1000);
+    } else {
+      if (intervalRef.current) {
+        clearInterval(intervalRef.current);
+      }
+    }
+
+    return () => {
+      if (intervalRef.current) {
+        clearInterval(intervalRef.current);
+      }
+    };
+  }, [isRunning, timeLeft, mode, cycles]);
+
+  const toggleTimer = () => setIsRunning(!isRunning);
+  
+  const resetTimer = () => {
+    setIsRunning(false);
+    setTimeLeft(getDuration());
+  };
+
+  const skipToNext = () => {
+    setIsRunning(false);
+    if (mode === 'work') {
+      const newCycles = cycles + 1;
+      setCycles(newCycles);
+      if (newCycles % 4 === 0) {
+        setMode('longBreak');
+        setTimeLeft(LONG_BREAK_MINUTES * 60);
+      } else {
+        setMode('shortBreak');
+        setTimeLeft(SHORT_BREAK_MINUTES * 60);
+      }
+    } else {
+      setMode('work');
+      setTimeLeft(WORK_MINUTES * 60);
+    }
+  };
+
+  const getModeLabel = () => {
+    switch (mode) {
+      case 'work': return 'Focus';
+      case 'shortBreak': return 'Short Break';
+      case 'longBreak': return 'Long Break';
+    }
+  };
+
+  const getModeColor = () => {
+    switch (mode) {
+      case 'work': return 'text-indigo-600 dark:text-indigo-400';
+      case 'shortBreak': return 'text-green-600 dark:text-green-400';
+      case 'longBreak': return 'text-blue-600 dark:text-blue-400';
+    }
+  };
+
+  // Compact view (icon only)
+  if (!isExpanded) {
+    return (
+      <button
+        onClick={onToggle}
+        className="relative p-2 text-gray-500 hover:text-gray-700 dark:text-gray-400 dark:hover:text-gray-200 transition-colors"
+        aria-label="Open timer"
+      >
+        <TimerIcon size={20} />
+        {isRunning && (
+          <span className="absolute top-1 right-1 w-2 h-2 bg-indigo-500 rounded-full animate-pulse" />
+        )}
+      </button>
+    );
+  }
+
+  return (
+    <div className="absolute right-0 top-full mt-2 w-72 bg-white dark:bg-gray-800 rounded-xl shadow-lg border border-gray-200 dark:border-gray-700 p-4 z-50">
+      {/* Header */}
+      <div className="flex items-center justify-between mb-4">
+        <div className="flex items-center gap-2">
+          <TimerIcon className={getModeColor()} size={18} />
+          <span className={`font-medium ${getModeColor()}`}>{getModeLabel()}</span>
+        </div>
+        <button
+          onClick={onToggle}
+          className="p-1 text-gray-400 hover:text-gray-600 dark:hover:text-gray-300"
+          aria-label="Close timer"
+        >
+          <XIcon size={18} />
+        </button>
+      </div>
+
+      {/* Timer Display */}
+      <div className="text-center mb-4">
+        <div className="text-4xl font-mono font-bold text-gray-900 dark:text-gray-100 mb-2">
+          {formatTime(timeLeft)}
+        </div>
+        
+        {/* Progress Bar */}
+        <div className="h-2 bg-gray-200 dark:bg-gray-700 rounded-full overflow-hidden">
+          <div
+            className={`h-full transition-all duration-1000 ${
+              mode === 'work' ? 'bg-indigo-500' : 'bg-green-500'
+            }`}
+            style={{ width: `${getProgress()}%` }}
+          />
+        </div>
+      </div>
+
+      {/* Cycles indicator */}
+      <div className="flex justify-center gap-1 mb-4">
+        {[...Array(4)].map((_, i) => (
+          <div
+            key={i}
+            className={`w-2 h-2 rounded-full ${
+              i < (cycles % 4) ? 'bg-indigo-500' : 'bg-gray-300 dark:bg-gray-600'
+            }`}
+          />
+        ))}
+      </div>
+
+      {/* Controls */}
+      <div className="flex items-center justify-center gap-3">
+        <button
+          onClick={resetTimer}
+          className="p-2 text-gray-500 hover:text-gray-700 dark:text-gray-400 dark:hover:text-gray-200"
+          aria-label="Reset timer"
+        >
+          <RotateCcwIcon size={18} />
+        </button>
+        
+        <button
+          onClick={toggleTimer}
+          className={`p-3 rounded-full ${
+            isRunning
+              ? 'bg-amber-100 text-amber-600 dark:bg-amber-900/30 dark:text-amber-400'
+              : 'bg-indigo-100 text-indigo-600 dark:bg-indigo-900/30 dark:text-indigo-400'
+          }`}
+          aria-label={isRunning ? 'Pause timer' : 'Start timer'}
+        >
+          {isRunning ? <PauseIcon size={20} /> : <PlayIcon size={20} />}
+        </button>
+        
+        <button
+          onClick={skipToNext}
+          className="p-2 text-gray-500 hover:text-gray-700 dark:text-gray-400 dark:hover:text-gray-200 text-sm font-medium"
+          aria-label="Skip to next"
+        >
+          Skip
+        </button>
+      </div>
+
+      {/* Mode switcher */}
+      <div className="mt-4 pt-4 border-t border-gray-200 dark:border-gray-700">
+        <div className="flex gap-2">
+          <button
+            onClick={() => { setMode('work'); setTimeLeft(WORK_MINUTES * 60); setIsRunning(false); }}
+            className={`flex-1 py-1 px-2 text-xs rounded ${
+              mode === 'work'
+                ? 'bg-indigo-100 text-indigo-700 dark:bg-indigo-900/30 dark:text-indigo-300'
+                : 'text-gray-500 hover:bg-gray-100 dark:text-gray-400 dark:hover:bg-gray-700'
+            }`}
+          >
+            Work (25m)
+          </button>
+          <button
+            onClick={() => { setMode('shortBreak'); setTimeLeft(SHORT_BREAK_MINUTES * 60); setIsRunning(false); }}
+            className={`flex-1 py-1 px-2 text-xs rounded ${
+              mode === 'shortBreak'
+                ? 'bg-green-100 text-green-700 dark:bg-green-900/30 dark:text-green-300'
+                : 'text-gray-500 hover:bg-gray-100 dark:text-gray-400 dark:hover:bg-gray-700'
+            }`}
+          >
+            Short (5m)
+          </button>
+          <button
+            onClick={() => { setMode('longBreak'); setTimeLeft(LONG_BREAK_MINUTES * 60); setIsRunning(false); }}
+            className={`flex-1 py-1 px-2 text-xs rounded ${
+              mode === 'longBreak'
+                ? 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-300'
+                : 'text-gray-500 hover:bg-gray-100 dark:text-gray-400 dark:hover:bg-gray-700'
+            }`}
+          >
+            Long (15m)
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+}