Move the extraScript machinery into the platformio package and tidy the extraction

tests/unit_tests/test_size_summary.py

@@ -128,13 +128,6 @@ def test_print_summary_handles_no_memory_types(
     assert capsys.readouterr().out == ""
 
 
-def test_format_bar_zero_total() -> None:
-    """A zero total must not divide by zero."""
-    from esphome.build_helpers.size_summary import format_bar
-
-    assert format_bar(0, 0) == "[          ]   0.0% (used 0 bytes from 0 bytes)"
-
-
 def test_print_summary_flash_line(
     tmp_path: Path, capsys: pytest.CaptureFixture[str]
 ) -> None: