Fix ruff lint findings across client, protocol, and tests

Resolve 51 findings from the I/RUF/BLE/TRY002/S110/PLR0402 rule set:

- Sort imports and __all__ (I001, RUF022, PLR0402). The sys.path.insert
  calls in check_public_calls.py and tests/test_e2e.py still precede the
  openttd imports that depend on them.
- Replace unused unpacked values with _ (RUF059) and annotate the two
  timetable lookup tables as ClassVar (RUF012).
- Narrow the best-effort excepts in OpenTTDClient.quit and
  OpenTTDAdminClient.quit to (OSError, SocketClosed) and log at debug
  rather than swallowing silently (BLE001, S110). The test doubles now
  raise an OSError subclass so they still exercise that branch.
- Narrow the gamescript JSON fallback to json.JSONDecodeError. The broad
  catch in receive_packet keeps a noqa: it guards untrusted wire data and
  must degrade to a no-op packet instead of killing the connection.
- Use contextlib.suppress instead of try/except/pass in tests.

ruff check . is clean, 102 tests pass, coverage stays at 100%.

Co-Authored-By: Claude <[email protected]>

check_public_calls.py

@@ -1,16 +1,17 @@
 #!/usr/bin/env python3
 import ast
 import inspect
-import sys
 import os
+import sys
 
 # Add lib and tests to path
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'lib'))
 sys.path.insert(0, os.path.dirname(__file__))
 
-from openttd import OpenTTDClient, OpenTTDAdminClient
-from openttd.protocol import OpenTTDProtocol, OpenTTDAdminProtocol
-import tests.test_e2e as test_e2e
+from openttd import OpenTTDAdminClient, OpenTTDClient
+from openttd.protocol import OpenTTDAdminProtocol, OpenTTDProtocol
+
+from tests import test_e2e
 
 # 1. Gather public functions dynamically at runtime using reflection
 classes = [OpenTTDClient, OpenTTDAdminClient, OpenTTDProtocol, OpenTTDAdminProtocol]