Build package, JSON-module and source-map indexes once instead of rescanning every observation list per file. Preserve first-observation lookup semantics when paths repeat and share each JSON lookup with the file projection.
Validation: duplicate-observation consumer regression and reconstruction suites. Flameox captured before/after CPU profiles on 3,000 JSON files; the complete CLI output stayed byte-identical. Exploratory samples do not establish an end-to-end timing improvement.