negative-difflisted

# Negative Diff Cleanup pass scoped to the current PR's recent additions. ## Scope - Last commit / current branch's added code only. - Do NOT delete legacy code you don't fully understand. ## Process 1. Run mechanical tools first: - `staticcheck ./...` - `deadcode ./...` - `unparam ./...` 2. For each new symbol added in this PR: - Two real callers? If no → delete or inline. - Existing equivalent in repo? If yes → reuse. - Added "for future use"? If yes → delete. - Interface with one implementation? If yes → replace with concrete. 3. For each new dependency: - Could 30 lines of stdlib replace it? If yes → remove. - Already a similar package in go.mod? If yes → consolidate. 4. For each new test: - Verifies only that the mock was called? If yes → rewrite or delete. - Could the test fail meaningfully? If no → rewrite. ## Output A delete-list: `file:line:symbol:reason`. Then minimal cleanup patches. ## Forbidden - Deleting load-bearing legacy code without understanding it. - Refactoring while deleting (one concern at a time). - Restructuring file organization (different concern). ## When this skill applies - After every Tier 1 cycle, before declaring done. - After any PR over 200 lines. - During quarterly cleanup passes (with `go-modernize`).