feat: add dynamic task fields and URI providers

[D3f0]

Summary

Closes #125.

• Adds typed Field(default=...), Field(default_factory=...), and required Field() task parameter defaults.
• Resolves omitted URI defaults through batched invoke_toolkit.field_resolver scheme providers.
• Preserves explicit CLI/direct/pre-task values; Field factories and providers do not run in help, listing, or completion.
• Adds intk -x create.package --provider <scheme> resolver-only package scaffolding.
• Documents the Field/provider API and adds regression coverage for parsing, typing, lifecycle isolation, resolver failures, cache keys, and generated provider packages.

Versioning

invoke-toolkit derives its version from git tags. No static version file requires editing. The Unreleased changelog has been updated. The PR title intentionally has no [bump ...] keyword, so merge will not trigger an automatic release.

Validation

• uv run pytest -q tests/test_fields.py tests/test_field_typing.py tests/test_annotated_help.py tests/test_file_completion.py tests/test_completion_with_choices.py tests/test_executor.py tests/extensions/test_create.py -k 'not create_package_create_venv_install_intk_and_package_and_list and not tasks_and_entrypoints_merge' -o addopts=''
  • 136 passed, 1 skipped, 2 deselected
• uv run ty check src/invoke_toolkit/tasks/fields.py src/invoke_toolkit/field_resolvers.py src/invoke_toolkit/tasks/tasks.py src/invoke_toolkit/extensions/tasks/create.py tests/typecheck/fields.py
• uv run ruff check src/invoke_toolkit/tasks/fields.py src/invoke_toolkit/field_resolvers.py src/invoke_toolkit/tasks/tasks.py src/invoke_toolkit/extensions/tasks/create.py tests/test_fields.py tests/test_field_typing.py tests/extensions/test_create.py tests/typecheck/fields.py tests/fixtures/future_fields.py

[D3f0]

Additional developments on this branch

Since the original PR description was written, this branch also includes:

• d478959 — Added task-local field resolvers, including resolver lifecycle isolation and related coverage.
• d5aa57e — Stabilized Nox and CI test environments.
• 5d628d6 — Made Nox sessions use isolated dependencies.
• cfb0c7b — Fixed Pylint pre-commit issues and completed the related import/type cleanup.

Current verification

• Full test suite: 725 passed, 18 skipped.
• Pylint pre-commit hook: passed.
• Branch is pushed and up to date with origin/feat/dynamic-task-fields.