refactor(src): Phase 10.2 batch 3 - project_manager + orchestrator_pm Result migration

project_manager.py (3 sites):
- get_all_tracks returns list[dict[str, Any]] where each dict now
  has an 'errors' field (list[ErrorInfo]) capturing per-track
  metadata recovery. The 3 SILENT_SWALLOW sites (state.from_dict,
  metadata.json, plan.md) now append to this list instead of
  silently passing.

orchestrator_pm.py (2 sites):
- get_track_history_summary returns Result[str]. The 2 SILENT_SWALLOW
  sites (metadata.json + spec.md reads) append to a scan_errors list
  that's threaded through the Result.

Tests updated to check result.ok and use result.data.

src/orchestrator_pm.py

@@ -8,14 +8,16 @@ from src import ai_client
 from src import mma_prompts
 from src import paths
 from src import summarize
+from src.result_types import Result, ErrorInfo, ErrorKind
 
 
-def get_track_history_summary() -> str:
+def get_track_history_summary() -> Result[str]:
  """
  Scans conductor/archive/ and conductor/tracks/ to build a summary of past work.
  [C: tests/test_orchestrator_pm_history.py:TestOrchestratorPMHistory.test_get_track_history_summary, tests/test_orchestrator_pm_history.py:TestOrchestratorPMHistory.test_get_track_history_summary_missing_files]
  """
  summary_parts = []
+ scan_errors: list[ErrorInfo] = []
  archive_path  = paths.get_archive_dir()
  tracks_path   = paths.get_tracks_dir()
  paths_to_scan = []
@@ -34,8 +36,8 @@ def get_track_history_summary() -> str:
      meta   = json.load(f)
      title  = meta.get("title", title)
      status = meta.get("status", status)
-   except (OSError, json.JSONDecodeError, UnicodeDecodeError):
-    pass
+   except (OSError, json.JSONDecodeError, UnicodeDecodeError) as e:
+    scan_errors.append(ErrorInfo(kind=ErrorKind.INTERNAL, message=str(e), source=f"orchestrator_pm.get_track_history_summary[{track_dir.name}].metadata", original=e))
   if spec_file.exists():
    try:
     with open(spec_file, "r", encoding="utf-8") as f:
@@ -46,12 +48,12 @@ def get_track_history_summary() -> str:
      else:
      # Just take a snippet of the beginning
       overview = content[:200] + "..."
-   except (OSError, UnicodeDecodeError):
-    pass
+   except (OSError, UnicodeDecodeError) as e:
+    scan_errors.append(ErrorInfo(kind=ErrorKind.INTERNAL, message=str(e), source=f"orchestrator_pm.get_track_history_summary[{track_dir.name}].spec", original=e))
   summary_parts.append(f"Track: {title}\nStatus: {status}\nOverview: {overview}\n---")
  if not summary_parts:
-  return "No previous tracks found."
- return "\n".join(summary_parts)
+  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]]:
  """