Add Knowledge Hub books FTS and remove training UI (0.16.0).

Index Assistent/books search.jsonl, expose knowledge hops/catalog in chat, and drop QLoRA/HF training stack.

Co-authored-by: Cursor <cursoragent@cursor.com>

AssistentMemory.Heard.cs

@@ -44,47 +44,10 @@ public sealed partial class AssistentMemory
 
     public void SetTrainSampleAgentLinked(string id, bool linked)
     {
-        if (string.IsNullOrWhiteSpace(id))
-        {
-            return;
-        }
-        lock (_lock)
-        {
-            EnsureTrainingReady();
-            if (!HasColumn("train_samples", "agent_linked"))
-            {
-                return;
-            }
-            using SqliteCommand cmd = _conn.CreateCommand();
-            cmd.CommandText = "UPDATE train_samples SET agent_linked = $v, updated_at = $u WHERE id = $id";
-            cmd.Parameters.AddWithValue("$v", linked ? 1 : 0);
-            cmd.Parameters.AddWithValue("$u", DateTimeOffset.UtcNow.ToUnixTimeMilliseconds());
-            cmd.Parameters.AddWithValue("$id", id.Trim());
-            cmd.ExecuteNonQuery();
-        }
+        // Training UI removed — no-op.
     }
 
-    public int CountAgentLinkedTrainSamples()
-    {
-        lock (_lock)
-        {
-            try
-            {
-                EnsureTrainingReady();
-            }
-            catch
-            {
-                return 0;
-            }
-            if (!HasColumn("train_samples", "agent_linked"))
-            {
-                return 0;
-            }
-            using SqliteCommand cmd = _conn.CreateCommand();
-            cmd.CommandText = "SELECT COUNT(*) FROM train_samples WHERE agent_linked = 1";
-            return Convert.ToInt32(cmd.ExecuteScalar());
-        }
-    }
+    public int CountAgentLinkedTrainSamples() => 0;
 
     public async Task<bool> LinkTrainSampleToAgentAsync(string baseUrl, JObject sample, string embedModel)
     {