style: apply ruff's automatic fixes and formatter

Mechanical only, and separated from the judgment calls that follow so the
reviewable changes are not buried in a 98-file whitespace diff.

227 automatic fixes: 60 blank lines carrying whitespace, 60 unsorted import
blocks, 34 Optional[X] to X | None, 28 unused imports, 16 deprecated typing
imports, 12 datetime.timezone.utc to datetime.UTC, and assorted smaller
modernisations. Then `ruff format` over src and tests: 98 files reformatted,
35 already conforming.

No file among the unused-import findings defines __all__ or is an __init__.py,
so nothing here removes a re-export.

`make test`: 658 passed, unchanged from HEAD.

Two things observed while verifying, neither addressed here:

`pytest tests/` cannot collect — tests/e2e/test_orchestration_e2e.py uses an
`e2e` marker that is not registered, and the config is strict about markers.
This fails identically at HEAD, so it predates this change; `make test` passes
because it ignores tests/e2e, tests/integration and tests/contracts.

test_tatlock_tool_call_logging_calculator is flaky. It failed once in a full run
with these changes and passed on the next, passes in isolation with them, and
fails in isolation at HEAD. It is order- or timing-dependent, not a regression
from this commit — established by running the full suite both ways rather than
by reasoning about which change could have caused it.

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

src/agents/housekeeper/tools.py

@@ -4,6 +4,7 @@ Housekeeper tools for PydanticAI agent.
 These tools wrap the core-api service and are registered with
 The Housekeeper agent for home automation tasks.
 """
+
 from src.agents.housekeeper.client import CoreAPIClient
 from src.core.logging_config import get_logger
 
@@ -72,14 +73,24 @@ async def list_devices(
                         return True
                     return False
 
-                sorted_devices = sorted(dom_devices, key=lambda d: (not is_room_group(d), d.entity_id))
+                sorted_devices = sorted(
+                    dom_devices, key=lambda d: (not is_room_group(d), d.entity_id)
+                )
 
                 for device in sorted_devices:
-                    state_icon = "on" if device.state == "on" else "off" if device.state == "off" else device.state
+                    state_icon = (
+                        "on"
+                        if device.state == "on"
+                        else "off"
+                        if device.state == "off"
+                        else device.state
+                    )
                     area_str = f" ({device.area})" if device.area else ""
                     # Mark room groups clearly using actual HA data
                     group_marker = " [ROOM GROUP]" if is_room_group(device) else ""
-                    output_parts.append(f"- **{device.name}**{area_str}{group_marker}: {state_icon}")
+                    output_parts.append(
+                        f"- **{device.name}**{area_str}{group_marker}: {state_icon}"
+                    )
                     output_parts.append(f"  ID: `{device.entity_id}`")
                 output_parts.append("")