codegraph: class instantiation not tracked as consumption

[carlos-alm]

Context

Discovered during Titan audit (phase: gauntlet, date: 2026-04-04).

Description

Error class instantiation (new ClassName()) is not tracked as consumption by the dead code detector. All error hierarchy classes in src/shared/errors.ts (CodegraphError, ParseError, DbError, etc.) appear dead despite 47 uses across 21 files via new ClassName(). Codegraph only tracks import-level references, not class instantiation.

Impact

All error classes incorrectly show 0 consumers, inflating dead symbol counts and causing false positives in dead code reports.

Source

• Titan phase: gauntlet
• Severity: bug
• Category: codegraph