Fix 9 bugs: ODT covered-cells, CSV BOM, HTML charset, stderr, dead code

- #13 (critical): Add CoveredTableCell elements to ODT for valid row spans (ODF 1.2)
- #28: Move "Total issues" info message from stdout to stderr (clean pipe output)
- #27: Wrap HTML export in full document with DOCTYPE and meta charset utf-8
- #26: Save CSV with utf-8-sig encoding (UTF-8 BOM for Excel compatibility)
- #31: Document CSV uses full project/version values (not display_* like console/MD)
- #30: Fix ODT header formatting when author is empty (no leading dot/space)
- #36: Remove test_cli_smoke_empty testing unreachable code path (return [])
- #37: Remove unused mock_path variable in ODT test fixture
- #34: Remove unreachable len(parts) != 2 check in parse_date_range

Closes #13, #28, #27, #26, #31, #30, #36, #37, #34

tests/test_cli.py

@@ -1,6 +1,4 @@
 import os
-import sys
-from io import StringIO
 from unittest import mock
 
 import pytest
@@ -38,21 +36,6 @@ def test_parse_date_range_invalid(date_arg):
         parse_date_range(date_arg)
 
 
-@mock.patch.dict(os.environ, VALID_ENV, clear=True)
-@mock.patch("redmine_reporter.cli.fetch_issues_with_spent_time")
-def test_cli_smoke_empty(mock_fetch):
-    """Пустой список задач -- выход 0, сообщение о 0 задачах."""
-    mock_fetch.return_value = []
-    captured = StringIO()
-    old_stdout, sys.stdout = sys.stdout, captured
-    try:
-        code = main(["--date", "2026-01-01--2026-01-31"])
-    finally:
-        sys.stdout = old_stdout
-    assert code == 0
-    assert "Total issues: 0" in captured.getvalue()
-
-
 @mock.patch.dict(os.environ, VALID_ENV, clear=True)
 @mock.patch("redmine_reporter.cli.fetch_issues_with_spent_time")
 def test_cli_returns_zero_on_no_entries(mock_fetch):
@@ -108,3 +91,26 @@ def test_cli_odt_missing_odfpy_message(mock_gf, mock_fetch, tmp_path, capsys):
     assert code == 1
     captured = capsys.readouterr()
     assert "odfpy" in captured.err
+
+
+class _MockIssue:
+    """Простой mock Redmine Issue для CLI-тестов."""
+
+    def __init__(self, issue_id=1, subject="Task", project="Project", status="New"):
+        self.id = issue_id
+        self.subject = subject
+        self.project = project
+        self.status = status
+        self.fixed_version = None
+
+
+@mock.patch.dict(os.environ, VALID_ENV, clear=True)
+@mock.patch("redmine_reporter.cli.fetch_issues_with_spent_time")
+def test_total_issues_message_goes_to_stderr(mock_fetch, capsys):
+    """«Total issues» пишется в stderr, не загрязняя stdout при pipe (#28)."""
+    issue = _MockIssue()
+    mock_fetch.return_value = [(issue, 1.0)]
+    main(["--date", "2026-01-01--2026-01-31"])
+    captured = capsys.readouterr()
+    assert "Total issues" not in captured.out
+    assert "Total issues" in captured.err