Add claude structured review output

[dbrosio3]

Summary

• Upgrade the Claude local AI adapter to use Claude Code native structured output via --output-format json and --json-schema.
• Feed Claude’s structured_output object through Pushgate’s shared native-object normalization path and local semantic validation.
• Preserve existing provider config, model selection, timeout handling, auth detection, read-only repo access, and provider-neutral verdict behavior.
• Tighten Claude structured-output envelope handling and keep exact provider CLI assertions at the provider adapter test surface.

Implementation Notes

• Reuses generateAiReviewOutputJsonSchema() from the canonical Zod review contract instead of duplicating schema definitions in the Claude adapter.
• Adds normalizeProviderReviewObject() for native structured providers while leaving text fallback normalization available for other adapters.
• Marks Claude as native_json_schema; Copilot remains on JSONL transport.
• Distinguishes unsupported structured-output behavior, malformed transport, invalid review objects, auth failures, timeouts, and command failures.
• Keeps hook-level tests focused on installed-hook flow rather than Claude-specific argument internals.

Tests

• pnpm test
• Focused coverage for:
  • successful Claude structured output
  • malformed Claude JSON transport
  • malformed Claude result envelopes
  • invalid structured review objects
  • unsupported --json-schema mode
  • Claude auth and generic command failures
  • source metadata preservation
  • installed-hook Claude invocation flow