Test index is stable for duplicate entries across regenerate, update

- Current incorrect behavior:
  All entries with duplicate compiled form are kept on regenerate
  but on update only the last of the duplicated entries is kept

This divergent behavior is not ideal to prevent index corruption
across reconfigure and update

tests/test_text_search.py

@@ -161,6 +161,40 @@ def test_asymmetric_reload(content_config: ContentConfig, search_models: SearchM
     content_config.org.input_files = []
 
 
+# ----------------------------------------------------------------------------------------------------
+def test_update_index_with_duplicate_entries_in_stable_order(
+    org_config_with_only_new_file: TextContentConfig, search_models: SearchModels
+):
+    # Arrange
+    new_file_to_index = Path(org_config_with_only_new_file.input_files[0])
+
+    # Insert org-mode entries with same compiled form into new org file
+    new_entry = "* TODO A Chihuahua doing Tango\n- Saw a super cute video of a chihuahua doing the Tango on Youtube\n"
+    with open(new_file_to_index, "w") as f:
+        f.write(f"{new_entry}{new_entry}")
+
+    # Act
+    # load embeddings, entries, notes model after adding new org-mode file
+    initial_index = text_search.setup(
+        OrgToJsonl, org_config_with_only_new_file, search_models.text_search.bi_encoder, regenerate=True
+    )
+
+    # update embeddings, entries, notes model after adding new org-mode file
+    updated_index = text_search.setup(
+        OrgToJsonl, org_config_with_only_new_file, search_models.text_search.bi_encoder, regenerate=False
+    )
+
+    # Assert
+    # verify only 1 entry added even if there are multiple duplicate entries
+    assert len(initial_index.entries) == len(updated_index.entries) == 1
+    assert len(initial_index.corpus_embeddings) == len(updated_index.corpus_embeddings) == 1
+
+    # verify the same entry is added even when there are multiple duplicate entries
+    error_details = compare_index(initial_index, updated_index)
+    if error_details:
+        pytest.fail(error_details)
+
+
 # ----------------------------------------------------------------------------------------------------
 def test_incremental_update(content_config: ContentConfig, search_models: SearchModels, new_org_file: Path):
     # Arrange