feat: OpenClaw session import with sorted history

Backend:
- New OpenClawEndpoint with GET /api/openclaw/sessions and POST /api/openclaw/import
- Lists all OpenClaw sessions with preview messages, model, summary
- Imports user/assistant text messages (skips tool-use/tool-result)
- Cleans user messages (removes webchat prefixes, cron tags, conversation info blocks)
- Re-import support: deletes previous openclaw-import chains before importing
- New DatabaseService methods: CreateChainForImport, CreateMessageForImport, DeleteOpenClawImport
- Added SortKey to MessageRecord (computed: openclaw-import gets id-10B, else id)

History sorting:
- OpenClaw-imported messages always appear before native messages
- Sort by CASE WHEN tag='openclaw-import' THEN id-10000000000 ELSE id END
- Cursor-based paging updated from beforeId/afterId to beforeSortKey/afterSortKey
- All history queries (GetLatestActive, Before, After, CountBefore) updated

Frontend:
- Dashboard: new 'OpenClaw Import' menu item in session card dropdown
- Modal: shows OpenClaw sessions with metadata, summary, preview messages
- Imported messages display blue 'OC' badge in chat
- API functions: apiGetOpenclawSessions, apiImportOpenclawSession
- History paging updated to use sortKey cursors

wwwroot/js/history.js

@@ -34,7 +34,7 @@ async function _autoLoadImageAttachments(messageId) {
 // ── History State ──
 
 let lastKnownMessageId = 0;
-let _oldestLoadedMessageId = 0;
+let _oldestLoadedSortKey = 0;
 let _hasMoreOlderMessages = false;
 let historyPollInterval = null;
 
@@ -50,7 +50,7 @@ async function loadHistory() {
 
     // Älteste geladene Message-ID merken für Nachladen
     _hasMoreOlderMessages = data.hasMore;
-    _oldestLoadedMessageId = _findOldestMessageId(entries);
+    _oldestLoadedSortKey = _findOldestSortKey(entries);
 
     if (data.hasMore) {
       showOlderMessagesButton(data.remainingCount);
@@ -76,7 +76,7 @@ async function loadHistory() {
 }
 
 async function loadOlderMessages() {
-  if (!_hasMoreOlderMessages || !_oldestLoadedMessageId) return;
+  if (!_hasMoreOlderMessages || !_oldestLoadedSortKey) return;
 
   const btn = chatEl().querySelector('.older-messages-btn');
   if (btn) {
@@ -86,12 +86,12 @@ async function loadOlderMessages() {
 
   try {
     const sid = getCurrentSessionId();
-    const data = await apiHistory(sid, _oldestLoadedMessageId, isDeletedVisible());
+    const data = await apiHistory(sid, _oldestLoadedSortKey, isDeletedVisible());
     const entries = data.entries || [];
 
     _hasMoreOlderMessages = data.hasMore;
-    const newOldest = _findOldestMessageId(entries);
-    if (newOldest > 0) _oldestLoadedMessageId = newOldest;
+    const newOldest = _findOldestSortKey(entries);
+    if (newOldest) _oldestLoadedSortKey = newOldest;
 
     // Button entfernen
     removeOlderMessagesButton();
@@ -145,10 +145,10 @@ async function loadOlderMessages() {
 
 // ── Helper Functions ──
 
-function _findOldestMessageId(entries) {
+function _findOldestSortKey(entries) {
   for (const entry of entries) {
     if (entry.messages && entry.messages.length > 0) {
-      return entry.messages[0].id;
+      return entry.messages[0].sortKey;
     }
   }
   return 0;
@@ -205,6 +205,7 @@ function _renderMessagesIntoFragment(fragment, msgs, imageMessageIds, opts) {
         const isReviewMsg = _isReviewMessage(msg.content);
         if (msg.role === 'user' && !isReviewMsg) {
           const div = _createMessageBubble({ role: 'user', timestamp: msg.createdAt, messageId: msg.id, isMarked: msg.isMarked, deletedOn: msg.deletedOn, archived });
+          if (msg.tag === 'openclaw-import') _addOpenClawBadge(div);
           renderUserContent(div, msg.content);
           _addBubbleActions(div, { timestamp: msg.createdAt, messageId: msg.id, deletedOn: msg.deletedOn, isMarked: msg.isMarked });
           fragment.appendChild(div);
@@ -224,6 +225,7 @@ function _renderMessagesIntoFragment(fragment, msgs, imageMessageIds, opts) {
           const div = _createMessageBubble({ role: 'assistant', timestamp: msg.createdAt, messageId: msg.id, isMarked: msg.isMarked, deletedOn: msg.deletedOn, archived });
           div.innerHTML = renderMarkdown(msg.content);
           parseFluentEmojis(div);
+          if (msg.tag === 'openclaw-import') _addOpenClawBadge(div);
           _addBubbleActions(div, { timestamp: msg.createdAt, messageId: msg.id, deletedOn: msg.deletedOn, isMarked: msg.isMarked });
           fragment.appendChild(div);
         }
@@ -379,6 +381,14 @@ function _renderReviewGroup(tagGroup, archived) {
   return bubble;
 }
 
+function _addOpenClawBadge(div) {
+  var badge = document.createElement('span');
+  badge.className = 'openclaw-badge';
+  badge.innerHTML = '<i class="fa fa-cloud-download"></i> OC';
+  badge.title = 'Importiert aus OpenClaw';
+  div.insertBefore(badge, div.firstChild);
+}
+
 function _isReviewMessage(content) {
   return content && (content.startsWith('[Review:') || content.startsWith('[Review-Feedback') || content.startsWith('[Finalizer:') || content.startsWith('[Preparer:'));
 }
@@ -429,7 +439,8 @@ function renderMessages(msgs, addToConversation) {
   chatEl().appendChild(fragment);
   // Track lastKnownMessageId
   for (const msg of msgs) {
-    if (msg.id > lastKnownMessageId) lastKnownMessageId = msg.id;
+    const sk = msg.sortKey || msg.id;
+    if (sk > lastKnownMessageId) lastKnownMessageId = sk;
   }
   // Auto-load image attachments
   for (const mid of imageMessageIds) _autoLoadImageAttachments(mid);