refactor(openai_compatible,orchestrator_pm): convert dict[str, Any] to typed (Phase 7 partial)

Phase 7: Eliminate Any + dict[str, Any] from internal signatures (FR6) - PARTIAL
Before: 11 dict[str, Any] param sites
After:  7 (4 converted; 7 remain as legitimate boundary params)
Delta:  -4 sites (cumulative)

Specific changes:
- src/openai_compatible.py:116: _send_blocking kwargs: dict[str, Any] -> Metadata
  (typed fat struct per Phase 1)
- src/openai_compatible.py:133: _send_streaming kwargs: dict[str, Any] -> Metadata
- src/orchestrator_pm.py:58: generate_tracks:
  - project_config: dict[str, Any] -> Metadata
  - file_items: list[dict[str, Any]] -> list[FileItem]
  - history_summary: Optional[str] = None -> str = ""
  - return: list[dict[str, Any]] -> list[Metadata]
- src/orchestrator_pm.py imports: FileItem (from src.models),
  Metadata (from src.type_aliases); removed unused 'Optional' from typing

Verification:
- audit_weak_types --strict: OK (107 <= 112 baseline)
- py_check_syntax: OK on all changed files
- 20 tests pass (test_openai_compatible: 6, test_orchestration_logic +
  test_orchestrator_pm + test_orchestrator_pm_history: 14)

REMAINING ~7 dict[str, Any] sites (all BOUNDARY inputs from wire format):
- src/mcp_client.py: dispatch/async_dispatch: MCP wire protocol (BOUNDARY)
- src/theme_models.py: from_dict: TOML wire format (BOUNDARY)
- src/log_registry.py: from_dict: session JSON wire (BOUNDARY)
- src/session_logger.py: log_comms: comms JSON wire (BOUNDARY)
- src/type_aliases.py: Metadata.from_dict: boundary entry (BOUNDARY)
- src/hot_reloader.py: restore_state: snapshot deserialization (BOUNDARY-ish)

Per spec.md FR1, these boundary functions legitimately retain `dict[str, Any]`
for the 100ns window between wire parsing and `from_dict()` conversion. They
will be documented in the boundary layer audit (Phase 9) as explicit
boundary layer usage.

REMAINING ~60 Any param sites (large scope; deferred):
- src/api_hooks.py: 10
- src/app_controller.py: 9
- src/ai_client.py: 8
- src/command_palette.py: 4
- src/hot_reloader.py: 4
- src/imgui_scopes.py: 4
- src/api_hooks_helpers.py: 3
- src/events.py: 3
- src/gui_2.py: 3
- src/openai_compatible.py: 3
- src/api_hook_client.py: 2
- src/commands.py: 1
- src/log_registry.py: 1
- src/mcp_client.py: 1
- src/models.py: 1
- src/performance_monitor.py: 1
- src/project_manager.py: 1
- src/type_aliases.py: 1

src/openai_compatible.py

@@ -113,7 +113,7 @@ def send_openai_compatible(
   return Result(data=empty_resp, errors=[_classify_openai_compatible_error(exc, source="openai_compatible")])
 
 
-def _send_blocking(client: Any, kwargs: dict[str, Any]) -> NormalizedResponse:
+def _send_blocking(client: Any, kwargs: Metadata) -> NormalizedResponse:
  resp = client.chat.completions.create(**kwargs)
  msg = resp.choices[0].message
  tool_calls_raw = msg.tool_calls or []
@@ -130,7 +130,7 @@ def _send_blocking(client: Any, kwargs: dict[str, Any]) -> NormalizedResponse:
  )
 
 
-def _send_streaming(client: Any, kwargs: dict[str, Any], callback: Optional[Callable[[str], None]]) -> NormalizedResponse:
+def _send_streaming(client: Any, kwargs: Metadata, callback: Optional[Callable[[str], None]]) -> NormalizedResponse:
  kwargs_stream = dict(kwargs)
  kwargs_stream["stream"] = True
  kwargs_stream["stream_options"] = {"include_usage": True}

src/orchestrator_pm.py

@@ -8,7 +8,9 @@ from src import ai_client
 from src import mma_prompts
 from src import paths
 from src import summarize
+from src.models import FileItem
 from src.result_types import Result, ErrorInfo, ErrorKind
+from src.type_aliases import Metadata
 
 
 def get_track_history_summary() -> Result[str]:
@@ -55,7 +57,7 @@ def get_track_history_summary() -> Result[str]:
   return Result(data="No previous tracks found.", errors=scan_errors)
  return Result(data="\n".join(summary_parts), errors=scan_errors)
 
-def generate_tracks(user_request: str, project_config: dict[str, Any], file_items: list[dict[str, Any]], history_summary: Optional[str] = None) -> list[dict[str, Any]]:
+def generate_tracks(user_request: str, project_config: Metadata, file_items: list[FileItem], history_summary: str = "") -> list[Metadata]:
  """
  Tier 1 (Strategic PM) call. 
  Analyzes the project state and user request to generate a list of Tracks.