refactor: nuke legacy harness, drop sdk_ prefixes

The SDK harness is the only path now; legacy host-side code is gone.
File names no longer carry the ``sdk_`` distinction.

Deleted legacy host-side modules:
- strix/agents/StrixAgent/ (template moved to strix/agents/prompts/)
- strix/agents/base_agent.py, state.py
- strix/llm/llm.py, config.py
- strix/runtime/docker_runtime.py, runtime.py
- strix/tools/executor.py, agents_graph/agents_graph_actions.py
- strix/interface/sdk_dispatch.py + the env-flag dispatch in cli.py

Renamed (drop ``sdk_`` prefix):
- strix/sdk_entry.py → strix/entry.py
- strix/agents/sdk_factory.py → strix/agents/factory.py
- strix/agents/sdk_prompt.py → strix/agents/prompt.py
- strix/tools/<x>/<x>_sdk_tool[s].py → strix/tools/<x>/tool[s].py
- strix/tools/_legacy_adapter.py → strix/tools/_state_adapter.py
- ``_legacy`` aliases inside the wrappers → ``_impl``

CLI + TUI now call ``run_strix_scan`` directly — they build the
sandbox image / sources_path locally and rely on
``session_manager.cleanup`` (called inside ``run_strix_scan``'s finally)
for teardown. Three TUI handlers that reached into legacy multi-agent
globals (``_agent_instances``, ``send_user_message_to_agent``,
``stop_agent``) are now no-ops with a TODO; reconnecting them to the
``AgentMessageBus`` is a follow-up.

Tracer.get_total_llm_stats no longer reaches into the deleted
``agents_graph_actions`` globals — the orchestration hooks now feed the
tracer via ``Tracer.record_llm_usage`` (live + completed buckets).
finish_scan's ``_check_active_agents`` and load_skill's runtime
``_agent_instances`` reach-in are no-op stubs; the
``AgentMessageBus`` is the source of truth post-migration.

llm/utils.py rewritten to keep only the streaming-parser helpers
(``normalize_tool_format``, ``parse_tool_invocations``,
``fix_incomplete_tool_call``, ``format_tool_call``, ``clean_content``).
``STRIX_MODEL_MAP`` moved to ``llm/multi_provider_setup.py`` (its only
remaining caller).

Per-file ruff ignores added for legacy interface modules (TUI / main /
CLI / utils / streaming_parser / tool_components) and tracer.py —
pre-existing PLC0415/BLE001/PLR0915 patterns are out of scope.

Tests: 287/287 passing. Renamed test files to drop ``sdk_`` prefix.
``test_tracer.py::test_get_total_llm_stats_aggregates_live_and_completed``
rewritten to feed ``Tracer.record_llm_usage`` instead of legacy globals.
Test file annotations added so pre-commit's strict mypy passes.

strix/interface/utils.py

@@ -20,6 +20,8 @@ from rich.console import Console
 from rich.panel import Panel
 from rich.text import Text
 
+from strix.config import Config
+
 
 # Token formatting utilities
 def format_token_count(count: float) -> str:
@@ -297,17 +299,15 @@ def build_final_stats_text(tracer: Any) -> Text:
     return stats_text
 
 
-def build_live_stats_text(tracer: Any, agent_config: dict[str, Any] | None = None) -> Text:
+def build_live_stats_text(tracer: Any) -> Text:
     stats_text = Text()
     if not tracer:
         return stats_text
 
-    if agent_config:
-        llm_config = agent_config["llm_config"]
-        model = getattr(llm_config, "model_name", "Unknown")
-        stats_text.append("Model ", style="dim")
-        stats_text.append(model, style="white")
-        stats_text.append("\n")
+    model = Config.get("strix_llm") or "unknown"
+    stats_text.append("Model ", style="dim")
+    stats_text.append(str(model), style="white")
+    stats_text.append("\n")
 
     vuln_count = len(tracer.vulnerability_reports)
     tool_count = tracer.get_real_tool_count()
@@ -370,15 +370,13 @@ def build_live_stats_text(tracer: Any, agent_config: dict[str, Any] | None = Non
     return stats_text
 
 
-def build_tui_stats_text(tracer: Any, agent_config: dict[str, Any] | None = None) -> Text:
+def build_tui_stats_text(tracer: Any) -> Text:
     stats_text = Text()
     if not tracer:
         return stats_text
 
-    if agent_config:
-        llm_config = agent_config["llm_config"]
-        model = getattr(llm_config, "model_name", "Unknown")
-        stats_text.append(model, style="white")
+    model = Config.get("strix_llm") or "unknown"
+    stats_text.append(str(model), style="white")
 
     llm_stats = tracer.get_total_llm_stats()
     total_stats = llm_stats["total"]
@@ -427,7 +425,7 @@ def _derive_target_label_for_run_name(targets_info: list[dict[str, Any]] | None)
         try:
             parsed = urlparse(url)
             return str(parsed.netloc or parsed.path or url)
-        except Exception:  # noqa: BLE001
+        except Exception:
             return str(url)
 
     if target_type == "repository":
@@ -443,7 +441,7 @@ def _derive_target_label_for_run_name(targets_info: list[dict[str, Any]] | None)
         path_str = details.get("target_path", original)
         try:
             return str(Path(path_str).name or path_str)
-        except Exception:  # noqa: BLE001
+        except Exception:
             return str(path_str)
 
     if target_type == "ip_address":