Debug Journal - Todo 5 agent loader repair

Started: 2026-07-06 Goal: Repair Todo 5 Gate B blockers in the senpi-task agent-definition loader with TDD and evidence.

Environment snapshot

• Runtime: Bun 1.3.14 / Node v26.0.0
• Worktree: /Users/yeongyu/local-workspaces/omo-wt/senpi-task-w0-agents
• Branch: code-yeongyu/senpi-task-w0-agents
• HEAD: 6152e8eff feat(senpi-task): markdown and omo.json agent definition loader
• References read: programming TypeScript README; debugging Node runtime, setup, investigation, fix, QA, cleanup; git-master.

Hypotheses

1. [CONFIRMED] Symlinked configured scan roots are followed because readdirSync traverses symlinked directories without an lstatSync boundary check.
2. [CONFIRMED] Directory read/scan failures are invisible because paths.ts catches Error and returns [].
3. [CONFIRMED] OMO config read failures escape because omo-overlay.ts calls readFileSync outside a catch.

Artifacts to revert

• None outside allowed source and evidence files.

Findings

• Existing code in paths.ts returns [] for filesystem Errors while scanning directories.
• Existing code in omo-overlay.ts catches JSONC parse/validation failures, but not filesystem read failures.