Function loadAnalysisContext

Load analysis context from the analysis pipeline output directory.

Scans {baseDir}/{date}/{articleTypeSlug}/ for a manifest.json and analysis markdown files in known subdirectories. When the directory does not exist or contains no analysis files, returns null for graceful degradation — strategies then behave exactly as before.

Handles suffixed directories (e.g. breaking-2, breaking-3) by scanning for the latest match.

Resolution order for base directory:

1. Explicit baseDir parameter (when non-default)
2. EP_ANALYSIS_DIR environment variable (set by orchestration)
3. Default 'analysis'

Resolution order for slug:

1. EP_ANALYSIS_SLUG environment variable (set by orchestration)
2. The articleTypeSlug parameter passed by each strategy