Formal Code Review — claude-opus-5

PR #7: feat: integrate exports and document APIs

No significant issues found in the reviewed changes.

Verification performed:

Re-exports work: Runtime import of src/index.js resolves all three names (classifyAltitudeBand, formatContact, normalizeCallsign). Extensioned relative specifiers are correct for "type": "module"; no circular imports (the two worker modules import nothing).
Scope respected: git diff --stat 6f40ba4..d4e6c38 shows exactly README.md, src/index.js, test/integration.test.js. No worker-owned implementation files touched.
Documentation accuracy: Boundary claims verified empirically — 9999→low, 10000→medium, 29999→medium, 30000→high, matching the documented <10k / 10k–<30k / ≥30k bands. The normalizeCallsign(' n-123 ab ') // => 'N123AB' example is exact. TypeError behavior on non-numeric/negative input confirmed.
No regression: formatContact body is unchanged; the pre-existing index.test.js suite still passes.
Tests: 22/22 pass, including the 4 new integration tests, which correctly target the integration concern (identity/reachability through the barrel) rather than duplicating unit coverage.
Security: No new inputs, dependencies, filesystem, or network surface. The /[\s-]/g regex has no backtracking risk.

Two observations deliberately not raised as blocking, noted only for transparency since this is a formal gate:

README documents formatContact's params as "a non-empty string" / "a finite non-negative number" while the implementation coerces via String()/Number(). This is a pre-existing implementation trait, the doc describes the contract rather than the coercion, and tightening it would require judgment about worker-owned behavior.
normalizeCallsign accepts coerced non-string input (e.g. numbers, per the existing worker test "handles numeric input coerced to string"), which the README doesn't mention.

Neither is a defect, neither affects the acceptance criteria, and neither would justify blocking this PR.