[PierreRaybaut]

Closes #123.

Pre-release fixes found while reviewing master before releasing 3.17.0.

Changes

• Version 3.17.0 — __version__ bumped to 3.17.0. The Unreleased section of the 3.16 release notes (Python 3.10 minimum, new get_pixmap function, new default font with Qt 5 on Windows, fallback for corrupted .mo catalogs) moves to the new doc/release_notes/release_3.17.md.
• DictItem in the JSON Schema export (bug fix) — DictItem uses its display callback to open the Qt dictionary editor from a button, with a (instance, item, value, parent, trigger_apply) signature. The JSON Schema module handled it as a reactive callback: DictItem fields were flagged with x-guidata-has-callback, and resolve_dataset_callbacks() raised TypeError: DictItem.__dictedit() missing 1 required positional argument: 'parent'. Frontends such as DataLab-Web call this function when a flagged field is edited. A private helper _get_reactive_callback() now ignores this callback (isinstance check, robust to renaming and subclasses) when flagging, running and resolving reactive callbacks.
• DateTimeItem display callback (bug fix) — DateTimeWidget connected dateTimeChanged to a lambda which only notified the value change, so its date_changed method was dead code and the display callback was never called. It is now connected, and the callback receives the Python value of the widget (datetime.datetime), like the other widgets. This is not a compatibility break, since the callback was never called before.
• about(html=False) (bug fix) — AboutInfo.about() only defined author and organization in its HTML branch, so plain-text output raised UnboundLocalError.
• French translations (bug fix) — Format ({}) should start with '%' was translated with the opposite meaning, and Export dataframe was marked fuzzy with an incomplete translation, so pybabel compile (used by the release workflow) left it out. The rest of the catalog is unchanged; it is already in sync with the source strings.
• Documentation — resolve_dataset_active is public and referenced by dataset_to_schema_with_values, but it was missing from the API reference: an autofunction directive is added.

Tests

• test_jsonschema.py::test_dict_item_editor_callback_is_not_reactive: no x-guidata-has-callback flag, values snapshot OK, resolve_dataset_callbacks() returns {}.
• New tests/unit/test_datetime_display_callback.py: changing the date/time in a DataSetEditLayout calls the callback once with a datetime.datetime, and the dataset is already updated.
• New tests/unit/test_about.py: plain-text and HTML output for AboutInfo and for guidata, with copyright_only in both modes.
• Each new test fails without its fix.

Local validation (Windows):

Binding	Python	Result
PyQt5 5.15	3.11	262 passed, 2 skipped
PyQt6 6.10	3.14	260 passed, 4 skipped
PySide6 6.10	3.14	260 passed, 4 skipped

• ruff check / ruff format --check: clean.
• French catalog: no missing, obsolete, fuzzy or untranslated entry; compiled with pybabel compile and both translations checked.
• Sphinx HTML build: resolve_dataset_active appears in the jsonschema reference page. The warnings are the same as on master, so this PR adds none.

Not included

Found during the same review, tracked separately:

• JSON Schema export: dynamic min/max/readonly properties are not supported #124 — dynamic min/max/readonly properties in the JSON Schema export;
• IntItem accepts booleans, including in strict JSON deserialization #125 — IntItem accepts booleans, including in strict JSON deserialization;
• DateItem display callback receives a QDateTime instead of a date #126 — the DateItem display callback receives a QDateTime instead of a date.

Downstream: DataLab already imports guidata.configtools.get_pixmap and will need guidata >= 3.17.0. This will be handled separately in DataLab.