fix: tighten OW background request filter to stop spurious task creation

Added three new detection patterns beyond the existing keyword checks:
1. Conversation history dumps: messages containing both "user:" and
   "assistant:" role markers — real user messages never have both
2. Context synthesis phrases: "provided context", "following conversation",
   "based on the conversation" (OW's query augmentation patterns)
3. Markdown template headers: "### " in messages >200 chars (OW uses
   section headers in background templates; real mobile messages don't)

This closes the gap that caused "Fix CobraTrans ESET" to be created
spuriously in Agent Ecosystem from an OW history-dump background request.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/intent.py

@@ -64,14 +64,30 @@ def classify_intent(message: str) -> str:
 
     # Open WebUI background tasks — sent automatically after every chat response.
     # They include the full chat history, so they'd mis-trigger execute/task intents.
-    # Patterns: "### Task:", "Query: <text>" (query augmentation), meta-task keywords.
+
+    # Pattern 1: OW meta-task headers and keyword phrases
     if (msg.startswith("### task:") or
             msg.startswith("query:") or
             "chat history" in msg or
             "summarizing the chat" in msg or
             "categorizing the main themes" in msg or
             "follow-up questions" in msg or
-            "3-5 word title" in msg):
+            "3-5 word title" in msg or
+            "provided context" in msg or
+            "following conversation" in msg or
+            "based on the conversation" in msg):
+        return "planning"
+
+    # Pattern 2: conversation history dumps — contain role marker pairs.
+    # Real user messages never contain both "user:" and "assistant:" labels.
+    if "user:" in msg and "assistant:" in msg:
+        return "planning"
+    if msg.count("user:") >= 2 or msg.count("assistant:") >= 2:
+        return "planning"
+
+    # Pattern 3: OW markdown template headers (### ) in long messages.
+    # Real mobile messages don't use markdown section headers.
+    if "### " in msg and len(msg) > 200:
         return "planning"
 
     # Project creation — check before task/query