debug(combat): add diagnostic logging to trace parser pipeline

Temporary verbose logs:
- CombatStatsTracker.Start() logs when timer starts
- ProcessChatLine logs first 3 invocations (text preview)
- OnSendTick logs first 3 sends (kill/damage/monster counts)

Will remove once we confirm the pipeline is working.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

MosswartMassacre/CombatStatsTracker.cs

@@ -44,6 +44,7 @@ namespace MosswartMassacre
             _sendTimer.Interval = SendIntervalMs;
             _sendTimer.Tick += OnSendTick;
             _sendTimer.Start();
+            _logger?.Log("[CombatStats] Tracker started (10s send interval)");
         }
 
         public void Stop()
@@ -67,6 +68,8 @@ namespace MosswartMassacre
         //  Public entry point — called from ChatEventRouter.OnChatText
         // ═══════════════════════════════════════════════════════════════
 
+        private int _parseCount;
+
         public void ProcessChatLine(string text)
         {
             if (string.IsNullOrEmpty(text)) return;
@@ -82,6 +85,13 @@ namespace MosswartMassacre
                 // Skip non-combat chat (tells, channels, etc.)
                 if (IsNonCombatChat(text)) return;
 
+                // Diagnostic: log first few parses to verify the pipeline is live
+                if (_parseCount < 3)
+                {
+                    _logger?.Log($"[CombatStats] ProcessChatLine invoked (#{_parseCount}): \"{text.Substring(0, Math.Min(text.Length, 80))}\"");
+                    _parseCount++;
+                }
+
                 // Detect prefix flags (Mag-Tools does this via text.Contains)
                 bool isCrit = text.Contains("Critical hit!");
                 bool isOverpower = text.Contains("Overpower!");
@@ -486,10 +496,15 @@ namespace MosswartMassacre
         //  Periodic send
         // ═══════════════════════════════════════════════════════════════
 
+        private int _sendCount;
+
         private void OnSendTick(object sender, EventArgs e)
         {
             if (!_dirty) return;
             _dirty = false;
+            _sendCount++;
+            if (_sendCount <= 3)
+                _logger?.Log($"[CombatStats] Sending snapshot #{_sendCount}: {_sessionState.TotalKills} kills, {_sessionState.TotalDamageGiven} dmg given, {_sessionState.Monsters.Count} monsters");
 
             try
             {