[TheGreatAxios]

Summary

Shared helpers replace duplicated provider, auth, tool-schema, git-index, and testkit paths.

• Provider adapters share error-body reading, JSON-rewrite and header mechanics, one Anthropic protocol identity, and one models-endpoint parser. Auth callback, login, session, store, and lock twins share seven helpers; provider-specific behavior stays explicit hooks.
• Tool input schemas come from arktype types. Context-store index writes batch inside one acquire. The dead-export guard runs on knip instead of ts-prune.
• Testkit shares reactor stubs, signal-aware spawn, and process waits. Shared stubs do not hide capabilities, the deleted director harness has no remaining imports, and waits still fail when the watched process or file is missing.

Verification

• Review of the testkit change: shared stubs do not hide capabilities; the deleted harness has no remaining imports; waits still fail when the watched process or file is missing.

Fixes CL-10670

[linear-code]

CL-10670

[corbits-triage]

Triage: Fail

@TheGreatAxios, please address the following:

• required checks are failing: static-analysis