Feature: Add message archiving system with browse-by-date selector

Implements automatic daily archiving of messages to improve performance
and enable browsing historical chat by date.

Backend changes:
- Add APScheduler for daily archiving at midnight (00:00 UTC)
- Create app/archiver/manager.py with archive logic and scheduler
- Extend parser.py to read from archive files and filter by days
- Add archive configuration to config.py (MC_ARCHIVE_*)

API changes:
- Extend GET /api/messages with archive_date and days parameters
- Add GET /api/archives endpoint to list available archives
- Add POST /api/archive/trigger for manual archiving

Frontend changes:
- Add date selector dropdown in navbar for archive browsing
- Implement archive list loading and date selection
- Update formatTime() to show full dates in archive view
- Live view now shows only last 7 days (configurable)

Docker & Config:
- Add archive volume mount in docker-compose.yml
- Add MC_ARCHIVE_DIR, MC_ARCHIVE_ENABLED, MC_ARCHIVE_RETENTION_DAYS env vars
- Update .env.example with archive configuration section

Documentation:
- Update README.md with archive feature and usage instructions
- Update .claude/instructions.md with archive endpoints

Key features:
- Automatic daily archiving (midnight UTC)
- Live view filtered to last 7 days for better performance
- Browse historical messages by date via dropdown selector
- Archives stored as dated files: {device}.YYYY-MM-DD.msgs
- Original .msgs file never modified (safe, read-only approach)

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

app/static/js/app.js

@@ -6,11 +6,15 @@
 let lastMessageCount = 0;
 let autoRefreshInterval = null;
 let isUserScrolling = false;
+let currentArchiveDate = null;  // Current selected archive date (null = live)
 
 // Initialize on page load
 document.addEventListener('DOMContentLoaded', function() {
     console.log('mc-webui initialized');
 
+    // Load archive list
+    loadArchiveList();
+
     // Load initial messages
     loadMessages();
 
@@ -55,6 +59,12 @@ function setupEventListeners() {
         loadMessages();
     });
 
+    // Date selector (archive selection)
+    document.getElementById('dateSelector').addEventListener('change', function(e) {
+        currentArchiveDate = e.target.value || null;
+        loadMessages();
+    });
+
     // Cleanup contacts button
     document.getElementById('cleanupBtn').addEventListener('click', function() {
         cleanupContacts();
@@ -79,7 +89,18 @@ function setupEventListeners() {
  */
 async function loadMessages() {
     try {
-        const response = await fetch('/api/messages?limit=100');
+        // Build URL with appropriate parameters
+        let url = '/api/messages?limit=500';
+
+        if (currentArchiveDate) {
+            // Loading archive
+            url += `&archive_date=${currentArchiveDate}`;
+        } else {
+            // Loading live messages - show last 7 days only
+            url += '&days=7';
+        }
+
+        const response = await fetch(url);
         const data = await response.json();
 
         if (data.success) {
@@ -354,6 +375,13 @@ function scrollToBottom() {
  */
 function formatTime(timestamp) {
     const date = new Date(timestamp * 1000);
+
+    // When viewing archive, always show full date + time
+    if (currentArchiveDate) {
+        return date.toLocaleDateString() + ' ' + date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
+    }
+
+    // When viewing live messages, use relative time
     const now = new Date();
     const diffDays = Math.floor((now - date) / (1000 * 60 * 60 * 24));
 
@@ -393,6 +421,47 @@ function updateCharCounter() {
     }
 }
 
+/**
+ * Load list of available archives
+ */
+async function loadArchiveList() {
+    try {
+        const response = await fetch('/api/archives');
+        const data = await response.json();
+
+        if (data.success) {
+            populateDateSelector(data.archives);
+        } else {
+            console.error('Error loading archives:', data.error);
+        }
+    } catch (error) {
+        console.error('Error loading archive list:', error);
+    }
+}
+
+/**
+ * Populate the date selector dropdown with archive dates
+ */
+function populateDateSelector(archives) {
+    const selector = document.getElementById('dateSelector');
+
+    // Keep the "Today (Live)" option
+    // Remove all other options
+    while (selector.options.length > 1) {
+        selector.remove(1);
+    }
+
+    // Add archive dates
+    archives.forEach(archive => {
+        const option = document.createElement('option');
+        option.value = archive.date;
+        option.textContent = `${archive.date} (${archive.message_count} msgs)`;
+        selector.appendChild(option);
+    });
+
+    console.log(`Loaded ${archives.length} archives`);
+}
+
 /**
  * Escape HTML to prevent XSS
  */