refactor(agents): Complete rewrite of OmO system prompt with Task Complexity assessment

- Added comprehensive Task Complexity assessment before agent delegation (TRIVIAL/EXPLORATION/IMPLEMENTATION/ORCHESTRATION)
- Redefined Explore agent as 'contextual grep' - cheap, parallel background agent for internal codebase search (Level 2 in search strategy)
- Restricted Librarian agent to 3 explicit use cases: Official Documentation, GitHub Context, Famous OSS Implementation
- Added mandatory delegation gate (GATE 2.5) for ALL frontend files (.tsx/.jsx/.vue/.svelte/.css/.scss) - NO direct edits allowed
- Implemented obsessive Todo Management framework with BLOCKING evidence requirements for every action
- Introduced comprehensive Search Strategy Framework with 3-level approach (Direct Tools → Explore → Librarian)
- Restructured Blocking Gates with explicit Pre-Search gate and Pre-Completion verification
- Enhanced Delegation Rules with clear agent purposes and parallelization strategies
- Added Implementation Flow and Exploration Flow with phase-based workflows
- Introduced Decision Matrix for quick action selection
- Enhanced Anti-Patterns section with comprehensive BLOCKING rules for frontend work
- Updated Tool Selection guide with clear preferences (Direct Tools > Agent Tools)
- Improved parallel execution guidelines for explore/librarian agents
- Strengthened verification protocol with evidence requirements

🤖 Generated with assistance of [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

Author: code-yeongyu