fix: preserve callable default None providers

[ApexWorm]

Problem

The dead-function detector reported intentional fail-closed providers whose literal return None value is used as a typed Callable dataclass default. This incorrectly flags the Frequency Coordination System no_current_tenant_id dependency provider despite active use.

Fix

Pre-index exact local and project-relative imported providers referenced by top-level typed dataclass callable defaults. Exempt only their literal return None bodies; pass, bare return, import-only, and general return-none functions remain findings.

Verification

• Ruff check on the changed tool files
• Focused smell tests: 60 passed
• Full Python smell suite: 284 passed
• Live project detector check: no dead-function match for access_contracts.py