Feature/async - v2.0.0 release candidate - #73

- Replace `requests` with `httpx` for sync/async HTTP support
- Extract shared logic into `SwgohComlinkBase` abstract base class
- Add `SwgohComlinkAsync` with identical API using async/await
- Refactor logging to follow Python library best practices (NullHandler only)
- Mask `secret_key` and `access_key` in `__repr__` and debug logging
- Add `_SENSITIVE_KEYS` frozenset and `_mask()` helper for consistent masking
- Sanitize kwargs in `func_debug_logger` to prevent credential leakage
- Add type annotations to Google-style docstrings for mkdocstrings
- Add mkdocs build step to CI workflow with `--strict` mode
- Add `SwgohComlinkAsync` API reference page to docs
- Update README with dedicated Async and StatCalc sections
- Rewrite `docs/logging.md` for NullHandler approach
- Add 110 unit tests (100% coverage on core modules)

- Introduce `docs/migration.md` covering dependency updates, exception handling, logging changes, and client lifecycle.
- Add migration summary to the README with key actions and a link to the full guide.
- Update `mkdocs.yml` to include the migration guide in the navigation.

…ncio-based scripts

- Removed the outdated `threaded_player_fetch.py` script.
- Added multiple new examples utilizing `SwgohComlinkAsync`, including:
  - `async/concurrent_requests.py`
  - `async/streaming_guild_roster.py`
  - `async/get_guild_leaderboard.py` and more for async capabilities.
- Updated `examples/README.md` with descriptions and directory structure for better organization between `Sync` and `Async` examples.

…oading

- Added `GameDataBuilder` and `GameDataBuilderAsync` modules to support dynamic game data generation from a running Comlink service instead of relying on static files.
- Enhanced README, API docs, and examples to demonstrate the use of `GameDataBuilder`.
- Updated examples for both sync and async workflows to showcase dynamic and static approaches to stat calculation.
- Updated `CHANGELOG.md` and bumped `StatCalc` functionality for this addition.

Refactor 1,970-line helpers.py into a focused helpers/ subpackage with
12 domain-specific modules. Consolidate 4 duplicate copies of stat data
into a single canonical source in _stat_data.py, eliminating ~800 lines
of redundancy including the 489-line inline STATS_NAME_MAP in
StatCalc/calculator.py. All existing import paths preserved via
backward-compatible re-export shim.

Add swgoh-migrate CLI tool (python -m swgoh_comlink.migrate) for
scanning user codebases to identify deprecated imports, API changes,
and migration steps needed when upgrading from v1.x.

Rewrite legacy test_get_enums and test_get_unit_stats from
requests/mock.patch to pytest-httpx, fixing 5 test failures.

…ulation

- Added logic to calculate and aggregate dismantle materials across multiple datacrons.
- Updated return type from `list` to `dict` for clearer representation of totals.
- Enhanced docstrings with detailed descriptions and type hints.

…t entries

- Grouped stat data imports in `helpers/__init__.py` for better organization and consistency.
- Removed unnecessary blank lines in `test_get_enums.py` and `test_parity.py`.
- Fixed minor import reordering in `_guild.py` for clarity.
- Corrected type hint formatting in `StatCalcAsync.create` method definition.

…nce CI

- Added fixtures in `conftest.py` for shared HMAC/Async test setup.
- Introduced new integration tests for HMAC and async clients, covering both valid and invalid key scenarios.
- Enhanced CI pipeline to include Python 3.14 and integration tests using separate workflows.
- Added integration tests for `SwgohComlink` and `SwgohComlinkAsync` clients, validating enums, metadata, events, and player-related operations.

…ight sentinel class

- Implemented custom `Sentinel` class to remove dependency on the external `sentinels` package.
- Updated `_sentinels.py` with the new implementation and revised sentinel definitions.
- Removed `sentinels` from `pyproject.toml` and lockfiles.
- Refactored `__all__` exports and updated imports to reflect the changes.

- Introduced comprehensive `Helpers` and `Exceptions` API reference documentation.
- Enriched `docs/index.md` with links to the new `Helpers` and `Exceptions` docs.
- Updated `mkdocs.yml` to include the new files in the navigation structure.
- Expanded helper module with new async methods for GAC and guild operations.

…GAC bracket handling

- Deleted `OPTIONAL` and `NotSet` sentinels from `helpers` and replaced their usage with type-based defaults (e.g., `None`, `int`).
- Updated `get_gac_brackets()` and `async_get_gac_brackets()` to use int-based `limit` parameter with a default value of `0` (no limit).
- Introduced exponential probing with binary search for GAC bracket boundary detection, optimizing performance from O(n) to O(log n).
- Added parallel batch fetching to `async_get_gac_brackets()` for faster operations via `asyncio.gather`.
- Adjusted docs, migration guide, and tests to align with these updates.

…patibility

- Updated payload serialization to use an empty string (`""`) instead of an empty object (`{}`) when no payload is provided, ensuring compatibility with comlink v4 (#51).
- Added unit test to verify updated behavior and prevent regressions.