fix(hooks): add null guard for tool.execute.after output

[sisyphus-dev-ai]

Summary

• Adds defensive null checks for output parameter in tool.execute.after hooks
• Fixes crash when /review command (and other Claude Code built-in commands) trigger hooks with undefined output

Problem

Claude Code's /review command triggers tool.execute.after hooks but passes output as undefined instead of the expected object with output, metadata, and title properties. This causes crashes when hooks try to access output.metadata.

Solution

Added early return guards in three locations (defense-in-depth):

1. Main orchestrator (src/index.ts): Guards all downstream hooks
2. Claude Code hooks (src/hooks/claude-code-hooks/index.ts): Additional safety layer
3. Atlas hook (src/hooks/atlas/index.ts): Additional safety layer

Changes

• src/index.ts: Add if (!output) return guard at start of tool.execute.after handler
• src/hooks/claude-code-hooks/index.ts: Add if (!output) return guard
• src/hooks/atlas/index.ts: Add if (!output) return guard
• src/hooks/atlas/index.test.ts: Add test for undefined output handling

Testing

• Added test case for undefined output in atlas hook tests
• All existing tests pass
• TypeScript typecheck passes

Fixes #1035

---

Summary by cubic

Add null guards in tool.execute.after to handle undefined output from /review and other Claude Code commands, preventing crashes. Fixes #1035.

• Bug Fixes
  • Guard against undefined output in the orchestrator and Claude Code/Atlas hooks.
  • Prevent metadata/output access when output is missing.
  • Add a unit test for undefined output handling in the Atlas hook.

^{Written for commit e9412bd. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 4 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.