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/delegation.py

@@ -8,6 +8,7 @@ returns a structured result for synthesis.
 This implements the agent-as-tool pattern recommended by PydanticAI:
 agents call other agents via tool wrappers, keeping each agent focused.
 """
+
 import asyncio
 from dataclasses import dataclass, field
 from enum import Enum
@@ -23,6 +24,7 @@ logger = get_logger(__name__)
 # Action Types for Think Slug Selection
 # =============================================================================
 
+
 class ActionType(Enum):
     """
     Categories of actions for selecting appropriate think messages.
@@ -30,11 +32,12 @@ class ActionType(Enum):
     Each expert has different action types that warrant different
     butler-perspective messages to the user.
     """
-    RETRIEVE = "retrieve"     # Looking up existing information
-    RESEARCH = "research"     # Conducting new research (web search, etc.)
-    CREATE = "create"         # Creating new content (pages, notes)
-    CONTROL = "control"       # Controlling devices/automations
-    RECORD = "record"         # Recording memories/notes
+
+    RETRIEVE = "retrieve"  # Looking up existing information
+    RESEARCH = "research"  # Conducting new research (web search, etc.)
+    CREATE = "create"  # Creating new content (pages, notes)
+    CONTROL = "control"  # Controlling devices/automations
+    RECORD = "record"  # Recording memories/notes
 
 
 # =============================================================================
@@ -159,8 +162,7 @@ def build_delegation_context(
         if isinstance(content, list):
             # Tolerate structured content parts
             content = " ".join(
-                part.get("text", "") if isinstance(part, dict) else str(part)
-                for part in content
+                part.get("text", "") if isinstance(part, dict) else str(part) for part in content
             )
         content = str(content).strip()
         if content:
@@ -206,6 +208,7 @@ class DelegationTask:
         depends_on: List of task IDs this task depends on
         result: Result from expert after execution
     """
+
     expert_name: str
     task: str
     context: str = ""
@@ -219,6 +222,7 @@ class DelegationTask:
         """Generate task ID if not provided."""
         if not self.task_id:
             import uuid
+
             self.task_id = f"{self.expert_name}_{uuid.uuid4().hex[:8]}"
 
 
@@ -236,6 +240,7 @@ class DelegationResult:
         error: Short user-safe error label if failed. Exception detail
             stays in the logs only
     """
+
     expert_name: str
     task: str
     success: bool
@@ -335,9 +340,7 @@ async def delegate_to_librarian(
 
             if span:
                 span.metadata["success"] = False
-                span.details["error"] = (
-                    f"timed out after {config.LIBRARIAN_TIMEOUT}s"
-                )
+                span.details["error"] = f"timed out after {config.LIBRARIAN_TIMEOUT}s"
 
             return DelegationResult(
                 expert_name="librarian",