refactor: fix unused imports, long lines, and type issues

Remove 35+ unused imports across 20+ files (W0611). Wrap 19 lines
to fit under 100 character limit (C0301). Add type casts and
annotations in egress_addon_core.py to resolve pyright errors
caused by JSON parsing of untyped objects.

Key changes:
- Remove unused imports (abstractmethod, mock utilities, etc)
- Split long lines at logical breaks (method calls, error messages)
- Add typing.cast() for proper type inference in JSON parsing
- Explicit type annotations for dict/list accesses

Results:
- Pylint rating: 8.73/10
- egress_addon_core.py: 0 pyright errors (was 15)
- All W0611 and C0301 issues fixed

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

tests/unit/test_smolmachines_prepare.py

@@ -59,7 +59,9 @@ class TestSmolmachinesResolveEnv(unittest.TestCase):
                     patch("bot_bottle.backend.smolmachines.prepare.PipelockProxy") as mock_pl,
                     patch("bot_bottle.backend.smolmachines.prepare.Egress") as mock_eg,
                     patch("bot_bottle.backend.smolmachines.prepare.Supervise"),
-                    patch("bot_bottle.backend.smolmachines.prepare.agent_provision_plan") as mock_app,
+                    patch(
+                        "bot_bottle.backend.smolmachines.prepare.agent_provision_plan"
+                    ) as mock_app,
                     patch("bot_bottle.backend.smolmachines.prepare.runtime_for"),
                 ):
                     mock_gg.return_value.prepare.return_value = MagicMock()