Added full support for the Bot API 9.6 (#1792)

* Added full support for the Bot API 9.6

* Add support for `managed_bot` updates

* Set `description_parse_mode` default to `"parse_mode"` and use `DateTime` for `addition_date` in `PollOption`

* Update changelog with features and changes from Bot API 9.6

* Add changelog fragment generator and update poll parameter descriptions

.serena/memories/codegen_workflow.md

@@ -0,0 +1,44 @@
+# Bot API Codegen Workflow
+
+## How code generation works
+aiogram uses `butcher` (via `aiogram-cli`) to auto-generate Python files from the Telegram Bot API schema.
+
+### Source of truth
+- `.butcher/schema/schema.json` — full parsed Bot API schema
+- `.butcher/types/<TypeName>/entity.json` — parsed entity metadata (DO NOT edit)
+- `.butcher/methods/<MethodName>/entity.json` — parsed method metadata (DO NOT edit)
+- `.butcher/enums/<EnumName>/entity.json` — parsed enum metadata (DO NOT edit)
+- `.butcher/templates/` — Jinja2 templates that produce Python code
+- YAML alias/override files in `.butcher/types/`, `.butcher/methods/` — edit these for customizations
+
+### Generated files (DO NOT hand-edit)
+- `aiogram/types/*.py` (except `base.py`, `custom.py`, `_union.py` — framework internals)
+- `aiogram/methods/*.py` (except `base.py`)
+- `aiogram/enums/*.py`
+- `aiogram/client/bot.py` (the `Bot` class shortcuts)
+- `aiogram/types/__init__.py`, `aiogram/methods/__init__.py`
+
+### Regeneration commands
+```bash
+uv run --extra cli butcher parse    # re-parse from API schema
+uv run --extra cli butcher refresh  # refresh entity JSON from parsed schema
+uv run --extra cli butcher apply all  # apply templates → generate Python files
+```
+
+### Adding a new type/method/shortcut
+1. Update the `.butcher` YAML alias/config file for the entity
+2. Run regeneration (parse → refresh → apply)
+3. Run lint + mypy + tests
+4. Commit both the `.butcher` config changes AND the generated Python files
+
+### API version bumps (maintainers)
+```bash
+make update-api args=patch   # or minor/major
+```
+This runs butcher parse/refresh/apply + version bump scripts that update:
+- `aiogram/__meta__.py`
+- `README.rst`
+- `docs/index.rst`
+
+## Key constraint
+The maintainers enforce: **never add types/methods/shortcuts by hand-editing generated files**. All changes must go through `.butcher` config so future regenerations preserve them.