What Problem This Solves

Ten helpers, constants, and one storage adapter type across src/shared were exported only for tests, leaving private implementation details in the production dead-export baseline.

Why This Change Was Made

Makes those symbols module-private. Tests retain Unicode node matching, Windows runtime-import normalization, runtime requirement evaluation, device-auth storage, silent-reply defaults, and token formatting coverage through the surviving production entry points.

Baseline delta: 1,265 → 1,255 (+0/-10). No Plugin SDK or documented package surface changes.

User Impact

No user-visible behavior change. Runtime eligibility, device authentication, node selection, lazy imports, silent replies, and subagent usage formatting keep their existing behavior.

Evidence

• Blacksmith Testbox tbx_01kxess9vbahndk349w0rsag8e, run 29290229006: exact regeneration byte-stable at 1,255; dead-export checker and formatting green
• Same Testbox: touched-path typed lint green; focused shared tests 56/56; core types green
• Follow-up on the same lease: tuple-inference repair proved with node-match 13/13 and core test types green
• Exact external-name search found no remaining test import of the privatized symbols
• Fresh autoreview: no accepted/actionable findings, patch correct at 0.96
• Latest main movement has no src/shared or baseline overlap