refactor: collapse strix/io/, strix/run_config_factory.py, strix/entry.py

Three top-level files that didn't earn their place:

- ``strix/io/scan_artifacts.py`` had a single consumer (the Tracer);
  collapsing it into ``strix/telemetry/`` puts it next to that consumer.
  ``strix/io/`` is gone.

- ``strix/run_config_factory.py`` held two helpers that didn't earn the
  factoring. ``make_agent_context`` was a 17-line dict-spelling function
  whose argument names were identical to its dict keys — replaced with
  inline dict literals at the two call sites. ``make_run_config`` had
  enough RunConfig assembly logic to justify a helper, but with only
  two callers (root scan + ``create_agent``) inlining is cleaner than
  keeping a top-level file. ``DEFAULT_RETRY`` moves to
  ``strix/llm/retry.py`` next to its other LLM-policy peers; the dead
  ``STRIX_DEFAULT_MAX_TURNS`` constant is dropped.

- ``strix/entry.py`` is a misnomer — it isn't *the* entry point (that's
  ``strix/interface/main.py`` for the CLI), it's the per-scan bring-up
  driver: build the bus, bring up the sandbox, build the root agent +
  child factory, format the scope-context block, register root in bus,
  open SQLiteSession, hand off to ``run_with_continuation``. That all
  lives next to its peers in ``strix/orchestration/`` now, renamed to
  ``scan.py`` so the role is obvious.

No behavior change. Net -125 LoC.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -211,7 +211,7 @@ ignore = [
 "strix/runtime/backends.py" = ["PLC0415"]
 # The vulnerability MD renderer is a long monolithic format function;
 # splitting per-section would obscure the structure without simplifying.
-"strix/io/scan_artifacts.py" = ["PLR0912", "PLR0915", "PERF401"]
+"strix/telemetry/scan_artifacts.py" = ["PLR0912", "PLR0915", "PERF401"]
 "strix/runtime/docker_client.py" = [
     "TC002",  # Manifest, Container imported for annotations
     "TC003",  # uuid imported for annotation
@@ -234,7 +234,7 @@ ignore = [
 # resolution past where mypy needs it. ``_build_root_task`` legitimately
 # walks every supported target type — splitting it into per-type
 # helpers would add indirection without simplifying anything.
-"strix/entry.py" = ["TC003", "PLR0912"]
+"strix/orchestration/scan.py" = ["TC003", "PLR0912"]
 # Tracer carries a long event surface and a runtime ``Callable``
 # annotation on ``vulnerability_found_callback``.
 "strix/telemetry/tracer.py" = ["TC003", "PLR0912", "PLR0915", "E501"]