fix(hook): support git-managed paths and local providers

[di-sukharev]

Summary

• resolve the effective hooks directory through Git so hook setup works with relative core.hooksPath values, submodules, and linked worktrees
• centralize provider configuration requirements and allow Ollama, MLX, and llama.cpp hooks to run without a fake API key
• add subprocess E2E coverage for hook path variants and credential behavior, with Git configuration isolated from the host environment
• rebuild the tracked CLI bundle so the fixes ship to npm consumers

Test plan

• npm run lint
• npm run test:unit -- --runInBand
• OCO_TEST_SKIP_VERSION_CHECK=true npx jest test/e2e/cliBehavior.test.ts test/e2e/geminiBehavior.test.ts test/e2e/gitPush.test.ts test/e2e/oneFile.test.ts test/e2e/noChanges.test.ts --runInBand

Closes #224
Closes #438