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/biographer/tools.py

@@ -10,6 +10,7 @@ These tools enable The Biographer to record and recall the user's story:
 For direct key-based access (get/set profile, preferences),
 use memory_service directly - these tools are for semantic queries.
 """
+
 from src.core.context import get_user
 from src.core.embeddings import get_embedding_client
 from src.core.logging_config import get_logger
@@ -23,6 +24,7 @@ logger = get_logger(__name__)
 # Semantic Recall
 # ============================================================================
 
+
 async def recall_semantic(
     query: str,
     memory_type: str = "",
@@ -108,6 +110,7 @@ async def recall_semantic(
 # Store Memory
 # ============================================================================
 
+
 async def store_insight(
     key: str,
     value: str,
@@ -158,7 +161,7 @@ async def store_insight(
                 f"**Keywords:** {', '.join(keywords)}",
                 f"**Importance:** {importance:.1f}",
                 "",
-                "_Memory is now searchable via semantic recall._"
+                "_Memory is now searchable via semantic recall._",
             ]
 
             logger.info(
@@ -216,7 +219,7 @@ async def update_profile(
                 "## Profile Updated",
                 f"**{key}:** {value}",
                 "",
-                "_Profile data is automatically included in context._"
+                "_Profile data is automatically included in context._",
             ]
 
             logger.info(
@@ -271,7 +274,7 @@ async def update_preference(
                 "## Preference Updated",
                 f"**{key}:** {value}",
                 "",
-                "_Preference will be applied to future responses._"
+                "_Preference will be applied to future responses._",
             ]
 
             logger.info(
@@ -293,6 +296,7 @@ async def update_preference(
 # List Memories
 # ============================================================================
 
+
 async def list_memories(
     memory_type: str = "learned_fact",
     limit: int = 20,
@@ -378,6 +382,7 @@ async def list_memories(
 # Forget Memory
 # ============================================================================
 
+
 async def forget_memory(
     key: str,
     memory_type: str = "learned_fact",
@@ -420,7 +425,7 @@ async def forget_memory(
                 f"**Key:** {key}",
                 f"**Type:** {memory_type}",
                 "",
-                "_Memory has been removed._"
+                "_Memory has been removed._",
             ]
 
             logger.info(